The game that brought you Max McGee and David Tyree could bring you Shiloh Keo, a potential member of the Unlikely Super Bowl Hero Hall of Fame.

Never heard of Keo, a Broncos backup safety? That’s the point. Last year, no one outside of Boston had a clue about Malcolm Butler before he saved the Super Bowl for the Patriots.

There is, of course, no guarantee Keo will go from anonymous to immortal like his big-game predecessors. But hear about his recent history and then argue he’s not on some date with destiny.

Less than two months ago, Keo was unemployed in Boise, Idaho, with a pregnant wife, two young boys (ages 4 and 1) and a sickening sense that it was time for Plan B, considering he hadn’t played in a regular-season NFL game in 23 months.

On Wednesday, though, he was chronicling how he’d gone from a personal crossroads to Super Bowl 50.

It’s an unlikely story that involves a desperate Twitter message to Broncos defensive coordinator Wade Phillips, a late-season interception that helped Denver clinch home-field advantage in the playoffs and a recovered onside kick that sealed the Broncos’ trip to the Super Bowl.

At one point, as he detailed his journey, Keo smiled. He’d just been hoping to get a job, man.

“It’s better than a dream come true,” he said, “because I never dreamt this way.”

The fairy-tale portion of Keo’s story was preceded by a fall from grace.

A 2011 fifth-round pick, Keo began his career with three solid seasons in Houston, where he played for Phillips, his defensive coordinator, and Broncos head coach Gary Kubiak. In 2012, he was named the special-teams captain. In 2013, he started 11 games at safety.

In 2014, however, he began to become intimate with pain, not all of it physical. He opened the season sidelined with a calf injury, was released after four games and was unemployed the rest of the season. In 2015, he signed with the Bengals, but was among their final roster cuts in September.

Three days after his release, he tried out for the Giants. Instead of a contract, though, he got a pulled hamstring running a 40-yard dash and went back to Boise.

He stayed there for three months, first rehabbing, then working out, then slowly coming to grips with his reality.

“Halfway through the season, frustration kicked in and my wife and I had to sit down and think about what’s best for our family,” Keo said. “We had to start thinking about those other options. What was my plan B going to be? It was really tough because I wasn’t out there making a living for my family.

“As a man, you feel like it’s your job to support your family and provide for them. Football was my life and what I’d known. When it was taken away, it was tough mentally and emotionally.”

Keo and his wife of five years, Keanna, came up with a compromise. He’d start contacting his former college and NFL coaches and hope to network his way into the next stage of his life, a coaching career.

However, he also wouldn’t shut the door on playing, and Keanna continued to support that dying dream. In fact, she encouraged him to reach out to his former defensive coordinator, Phillips, who is active on Twitter.

Keo, who had lost Phillips’ cell-phone number, was hesitant. Lobbying for an NFL job on social media was embarrassing, but he was in nothing-to-lose mode. On Dec. 1, after the Broncos had signed safety Josh Bush to assist their injury depleted secondary, he sent this message to Phillips: “didn’t want to pick me huh?”

Phillips responded nine minutes later by saying he thought highly of Keo and explained the team’s reasoning for signing Bush. Keo ended the cordial back-and-forth by asking Phillips to keep him in mind.

Evidently Phillips got the message: On Dec. 9, after more injury issues, the Broncos signed Keo.

Phillips doesn’t regret the move, but the signing has come with an unexpected cost: He has received a deluge of social-media resumes.

“If people would quit Twittering me now to try to get on the team, I’d appreciate it,” Phillips said, smiling. “I’ve had thousands of people say, ‘Hey, I played in junior high and know I can help you.’”

Keo has helped the Broncos. Three weeks after he signed, he returned an interception 22 yards with five minutes left in the fourth quarter of a tie game with the Chargers. On the next play, a 23-yard touchdown run gave the Broncos a 27-20 win that clinched home-field advantage in the postseason.

Three weeks later, Keo played 36 defensive snaps in a 20-18 AFC Championship Game win over the Patriots after injuries sidelined starting safeties Darian Stewart and T.J. Ward. With 12 seconds left, he darted forward to recover Stephen Gostkoswki’s straight-ahead onside kick 6 yards beyond the line of scrimmage.

The daring recovery secured a trip to Santa Clara for Keo, who remains unheralded enough to qualify for who’s-he star status Sunday.

If he doesn’t, however, that’s OK. From out of football to the Super Bowl?

He never even dreamt like that.

Eric Branch is a San Francisco Chronicle staff writer. E-mail: ebranch@sfchronicle.com Twitter: @Eric_Branch