Michael Perez/Associated Press

The only NFL general manager below the age of 40 is celebrating his birthday on Monday.

Just how young is Howie Roseman?

Well, less than 15 years ago, he was working as an unpaid intern at the bottom of the Philadelphia Eagles' corporate ladder.

Less than 20 years ago, he and current Jacksonville Jaguars offensive coordinator Jedd Fisch were dreaming of their wildly unrealistic NFL futures as football fanatical roommates at the University of Florida.

And only 32 years ago, Roseman was a first-grader on a plane to visit his grandparents in Florida.

I only mention that because it was on that flight that the football-obsessed seven-year-old was serendipitously seated near San Jose State head football coach Jack Elway—you know, John's dad—who was so blown away by young Howie's football passion that he left his business card with his mom and told him to call when he graduated high school.

Officially, Roseman turns 39 on Monday, but he's been in the Eagles' front office since he was 24. This is the only organization he's ever been employed by, and the NFL's youngest general manager is starting to make waves league-wide with his savvy salary-cap management and smart drafting.

His young, homegrown core in Philadelphia has been shored up for years to come, with smart extensions, and the franchise has more salary-cap space than all but four other NFL teams, according to Over the Cap.

But because he's so young and because his rise to personnel king in Philly was cloaked by the presence of accomplished headliners such as Joe Banner and Andy Reid, Roseman remains somewhat of a mysterious figure in the NFL community.

In order to shed some light on how he became one of the NFL's most respected executives in such a short time, here are 10 facts about Howie Roseman.

1. He sent over 1,000 letters to NFL teams before finally landing an internship with the Eagles

His best estimate is about 1,100, actually. One letter to each team three or four times a year between his senior year in high school and his third year of law school (he did that math on the spot and at a speed much faster than us).

"Rejections stacked as high as the ceiling in any room in your house," he said in an exclusive interview with Bleacher Report.

When he finally landed an unpaid internship under Banner in Philadelphia, Roseman was a 24-year-old who had placed all of his eggs in one basket.

"I never wanted to do anything else," said Roseman. "I really didn't have a backup plan, which, looking back on it, probably wasn't so smart."

But a lot of that desire goes back to that fateful flight to visit grandma and grandpa. Young Howie and his family were seated near the bathroom, giving Jack Elway a chance to catch the New York kid in his Yankees hat.

He asked Roseman if he was a fan, since John had been drafted by the Bronx Bombers. That sparked a two-hour sports conversation between the legend and the seven-year-old, with Roseman relocating to an empty seat next to Elway.

Roseman came away from that experience confident that he could one day become a football legend himself.

"I held on to it like it was someone who believed in me like I believed in myself," he said of the chance encounter. "I used to tell people when I was 13 years old I was going to be a GM in the National Football League. And they had a laugh at me, understandably so."

Roseman was captivated by the game even before meeting Elway, but his ability to impress the man on that flight was a strong indication he also had the brain for it. What's scary, though, is that his oldest son, who is now that same age of seven and who attended the NFL draft last month, is "way ahead of where I was at that age," according to Roseman.

Something tells us that if that boy decides to pursue the same dream, he won't have to send out 1,000 or more letters in order to land his first NFL gig.

2. He may or may not have stalked Mike Tannenbaum

The first NFL executive to give Roseman the time of day was Tannenbaum, who at the time was the New York Jets' pro personnel director before eventually becoming the GM in New York. The second was Banner, who was the executive vice president in Philly. Turns out, Roseman became the butt of a joke between the two.

"It was kind of a joke," said Roseman, "about a guy who was kind of on the verge of being this stalker."

As you can probably guess, it had something to do with all of those letters.

"Could somebody be that persistent and be normal?" joked Tannenbaum to Mike Jensen of The Philadelphia Inquirer in 2010.

"Was this guy the most persistent guy in the history of America or was he crazy?" Banner said in 2010, per Jensen. "Should we stay away from him, or should one of us interview him?"

Eventually, both men interviewed Roseman. Banner's Eagles gave him the internship that led to his entry-level role in 2000 that led to his director of football administration role in 2003 that led to his vice president of football administration role in 2006 that led to his vice president of player personnel role in 2008 that led to his promotion to general manager in 2010.

"He goes all in at everything he does," Fisch told us. "I knew that whatever he said he was going to be, he was going to become."

The rest is history.

3. He has never played organized football

Michael Perez/Associated Press

While working that first internship with the Eagles, Roseman was still commuting from New York each day. Born in Brooklyn but raised in Marlboro, New Jersey, he was the only member of his family who was enthusiastic about sports.

Growing up, he'd watch games by himself, and he took a special interest in the draft process and how teams are built. But because his parents weren't familiar with the game, they never granted kid Howie the permission to play.

"I wanted to play," said Roseman, "but it didn't take long for me to see that with the size difference between me and my friends who were playing, that that wasn't really my career route."

So while everybody else in his age group dreamed of playing pro sports, Roseman was the only young American who instead fantasized about one day running a pro sports team.

That was the case until he ran into Fisch, who became his roommate while attending the University of Florida. Coincidentally, the two fraternity brothers were both sure they wanted to become employed by NFL franchises, something Fisch realized when the draft rolled around.

"He walked downstairs with a full draft board," recalled Fisch. "And I was trying to figure out what he was doing, and he said he does this every year. So we really started at that point in time talking about the similar interests we had."

So while running into Elway in grade school might have pushed Roseman to pursue his dream, an extra push from Fisch might have been a game-changer.

"Us being able to discuss things, bounce things off each other [was important]," said Fisch. "Knowing that there's somebody there that before you were even part of the National Football League you had similar goals and aspirations."

4. He has a law degree

But Roseman never figured he'd spend much time in courtrooms. He wanted to be an NFL general manager, and, as he told us, there really was no backup plan in place. Instead, his decision to use his 3.8 GPA in order to attend Fordham University School of Law was based on the idea that he could specialize as a salary-cap expert and slick negotiator.

But it was Tannenbaum who originally suggested Roseman go that route. He lacked football pedigree, and the cap was still in its relative infancy. Roseman needed a niche, which he carved out at Fordham. Later, in Philadelphia, he'd have a chance to add college and pro scouting experience to his resume, completing the package.

5. He came extremely close to joining the Jets instead of the Eagles

Julio Cortez/Associated Press

It would have been extra special had Tannenbaum been able to hire Roseman out of school, since Roseman grew up in the New York area as a devout Jets fan.

And that almost happened.

In 1999, he was one of three finalists for an entry-level personnel gig with Gang Green. Tannenbaum went with another candidate, but he also made the effort to put in a good word with Banner.

"The best things that happen to you," said Roseman of an experience that at the time must of have disappointing, "are the things you think you want but don't end up getting."

And while we'll never know where he'd be today had Roseman, instead, become a Jets employee in '99, the odds indicate that final rejection was probably the best thing that ever happened to him.

In Philly, he joined a young organization with a brand-new head coach in Andy Reid and an open-minded front office. It was the type of place where a gifted young dude had a real chance to climb.

And that's exactly what Roseman would do. Hell, 11 years later, he was practically running the joint.

6. He owes a lot to Joe Banner

Matt Rourke/Associated Press/Associated Press

When Banner finally brought him in that year as an unpaid intern, Roseman didn't even have a place to sit. So they placed him at the end of an administrative assistant's desk. According to that Inquirer story, his first "real office" was originally a supply closet and, once again, is now.

When he was hired on, he was paid only $250 per week. That might not be so jarring if we were profiling a 75-year-old exec who got his first job in a mail room in 1958, but this was this century.

But along the way, Banner and the rest of Roseman's bosses indicated that they strongly believed in his abilities.

"When I got hired in Philadelphia," said Roseman, "I told them that at some point I'd like to be involved in personnel. I had a passion for it, and I felt like it was an area that I could contribute to.

"And what they told me was, 'We don't have any doors in this organization. The most important thing is showing that you do something really well and that people can rely on you for the strength that we hired you for. And if you show that, at some point we'll circle back.' And they were true to their word."

Seriously. He asked for the chance to work on his scouting chops, and they allowed him to go on scouting trips. He clearly had an interest in the salary cap, and they had him perform contract research for draft picks. He had a law degree and a penchant for negotiating, and before the guy was 30, Banner had granted Roseman the ability to negotiate player contracts.

Banner and the Eagles split in less-than-smooth fashion in 2012, and implications sprang up last year that he was the source of negative comments regarding Roseman published by Jason La Canfora of CBS Sports (something Banner denied). Regardless, the relationship between Banner and his former cohorts in Philly is considered by many to be rocky at best.

But Roseman tells us that he's still on good terms with his first NFL boss, and he won't soon forget the opportunities Banner created for him.

"I'm appreciative of him," said Roseman, "and always wish him and his family the best at whatever they do."

7. He regrets splurging in 2011

Rich Schultz/Associated Press

Remember the "Dream Team"? Feels like a century ago, mainly because Banner and Reid were still in town and Roseman was still viewed by outsiders as a man who wasn't calling the shots. But in his first full offseason in the general-manager role, Roseman rolled the dice by breaking from his philosophy on homegrown talent and went on a free-agent spending spree.

In came cornerbacks Nnamdi Asomugha, Dominique Rodgers-Cromartie, defensive end Jason Babin, running back Ronnie Brown, wide receiver Steve Smith, defensive tackle Cullen Jenkins and backup quarterback Vince Young.

Roseman admitted he wasn't "staying true to the principles that I believed in" with so many uncharacteristic and expensive signings. And unsurprisingly, most of those moves backfired, as Philly won just 12 games over the next two seasons.

"When we look back at that, I think being in five NFC Championship games, getting so close, I think you get in a moment where you feel like you have to put all your chips in the center of the table," Roseman told us.

"That was counter to everything we had built in Philadelphia. It goes back to how important culture and chemistry is to your football team, drafting the right players, having homegrown talent that you're able to sign to contract extensions. I think we did a good job of getting back to the way that we believe in."

But Roseman does feel he learned from those mistakes.

"Certainly being young, I don't have all the answers," he said. "Everything you go through is a lesson, and it helps you form the kind of organization that you're looking for."

Look at the current roster, though, and you'll find more than a few key players who were homegrown. Yeah, they use free agency to add new pieces to the puzzle, but this team's core—Nick Foles, LeSean McCoy, Jeremy Maclin, Fletcher Cox, Trent Cole and 80 percent of the offensive line—was built in the draft.

8. He doesn't fear the team's decision to get rid of DeSean Jackson might backfire

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The gutsiest move thus far in Roseman's GM tenure came earlier this offseason, when he, head coach Chip Kelly and the rest of the front office decided to cut ties with Pro Bowl wide receiver DeSean Jackson, who was coming off a career year.

But it's important to keep in mind that Roseman had dealt with another ordeal involving a controversial receiver when the excrement hit the fan with Terrell Owens in 2005. At the time, Roseman, who is actually a year younger than Owens, was director of football administration. He didn't necessarily have much say in the team's decision to part ways with T.O., but he admits it helped him grow.

"It was an incredible learning experience for me in trying to figure out, when you hopefully get an opportunity one day, how you make those decisions and the factors in play," said Roseman. "It was never about one player, because in this game you lose players. Injuries do happen.

"So when Donovan McNabb gets hurt or you have to go in a different direction, with T.O.—if you put one player on a pedestal in this league, then how does the rest of the team react? It's just such a team sport that when you see those examples and how the team rebounds, it's because of the leadership in the organization."

In our conversation, Roseman—who has insisted from the get-go that Jackson's release was purely a "football decision"—spoke only abstractly about those non-football factors that many felt were linked to that particular move.

"It's about the team," he said. "It's about building the team and trying to make sure that you have the right combination of personnel. I'm not talking about [Owens or Jackson] in particular, but you have to make tough decisions. And when you're talking about it, you're dealing with the salary cap and a number of resources. So in this business you're going to have to make tough decisions."

I think the most important takeaway from that shocking decision to cut Jackson is that Roseman and his peers are willing to make perceived sacrifices if they feel it'll pay off in the long run.

"Through Howie's tenure as the director of personnel and then general manager, there's been some aggressive moves," said Fisch, who has been keeping close tabs on Roseman's progress from Jacksonville. "So there's nothing really surprising when it comes to what Howie's doing. He's going to do what he thinks is in the best interest of the team."

And in order to be that bold, you can't afford to look in the rear-view mirror.

"You have to have an aggressive mentality in this business," Roseman said. "You have to make tough decisions. And you're not always going to be perfect on the decision-making, but you gotta have a good batting average, and you gotta do the right thing for your football team. And it may not be the same decisions other people wouldn't make, but you have to be confident in that direction, and you can't have a fear of failure."

9. He doesn't have a desire for full autonomy

Roseman still splits control with Kelly, just as he did with Reid before that coaching change took place last January. But while his stock continues to grow, he insists he isn't interested in getting to a point at which he has the final say when it comes to all roster-related decisions.

"Maybe it's the way I was raised in this business, but when you're in personnel in the National Football League, it's about making sure you get the proper fighters for the coaching staff," Roseman said. "I think it's a huge plus for us to really empower the coaches, because those are the guys that are going to put [the players] in a position to succeed. So I think that's the way it should be."

10. Although he's accomplished his childhood dream, his next goal is to bring a championship to Philadelphia

Matt Rourke/Associated Press

While it's great that Roseman is already living his dream before turning 40, the reality is that Eagles fans won't be satisfied until he can help bring a first Lombardi Trophy to the increasingly impatient football hotbed of Philadelphia.

And he's well aware. That's part of what keeps him driving forward, despite the fact he's already at the top.

"It's two things," Roseman said of what lights a fire under him entering his fifth season as GM.

"One, you feel a responsibility to your owner and to the fans to put [the franchise] in a great place—to build something that lasts and build a culture and chemistry that lasts. And then two, it is about winning a world championship. And knowing the passion of our fans and the support that we get year in and year out, 365 days a year, it would change lives. So that drives you."

Considering the borderline-stalker lengths Roseman went to in order to get this job, any indication that he's still just as driven when it comes to winning a Super Bowl should be encouraging for Eagles fans everywhere.