Quinn Cook was in the fourth grade when he first heard about a gangly high school freshman named Kevin Durant.

At 6-foot-3 and rail thin, Durant had been overlooked by many of the high-profile, local private schools in the Washington, D.C., area. It was Cook’s AAU coach with the PG Jaguars, Taras “Stink” Brown, who told him to study how Durant worked out.

“When I met (Kevin), he wasn’t the best in the city or anything,” recalled Cook, who signed a two-way contract last week with the Warriors. “He was just a tall kid who could shoot, but you could see his work ethic. You just saw him every day getting better and better. He taught me how to really work.”

It is a blueprint Cook, 24, has relied on while pursuing a long-term role in the NBA. Little more than two years after going undrafted out of Duke, the 6-foot-2, 179-pound point guard has been waived four times and signed three 10-day contracts, with the Mavericks and Pelicans. Now on his fourth NBA team in seven months, Cook hopes to find stability with Durant and Golden State.

General manager Bob Myers brought Cook in for insurance behind Stephen Curry and Shaun Livingston. As one of the team’s two two-way players, Cook can spend up to 45 days with the Warriors and the rest of the season with their Gatorade League affiliate in Santa Cruz. His $75,000 G-League salary is augmented by a prorated portion of the NBA rookie minimum salary — roughly $816,000 this season — for any days he is with the big club.

Cook was with Golden State for a week, his only game action a garbage-time cameo in Saturday’s loss at Memphis, before joining Santa Cruz for training camp Wednesday. The plan is to limit his days with the NBA team to ensure he is available to provide depth should an injury or rest deplete the Warriors’ backcourt. With Livingston attending a funeral in Dallas, Cook was called up for Friday’s win over his hometown Wizards.

“He’s a guy who you wouldn’t think is a young player,” Golden State head coach Steve Kerr said. “He kind of conducts himself like he’s a 10-year vet, and I mean that in a positive way. He’s just really professional and hardworking and no nonsense. I’m a big fan.”

Cook grew up idolizing many promising prospects on Washington’s neighborhood basketball courts. In an AAU system built on hype, Durant’s unassuming approach made him stand out to a young Cook.

Though Durant had won multiple national AAU championships with lifelong friend Michael Beasley and the PG Jaguars, he was largely ignored in middle school by the area’s most respected high school coaches. A few weeks into ninth grade at his local public school, Suitland High, Durant transferred to nearby National Christian Academy after his training partner, Charlie Bell, persuaded the coach there to watch Durant work out.

Around that time, Brown, whom Durant considers his godfather, introduced Durant to Cook. Even then, as Cook starred on the PG Jaguars’ Under-10 team, Durant could see in the elementary schooler an unyielding desire to win.

After three years at DeMatha Catholic High School in Hyattsville, Md., Cook attended Oak Hill Academy to emulate the success Durant — who attended the school for his junior season — and fellow Washington-area blue-chippers Beasley, Nolan Smith and Ty Lawson had enjoyed at the prep powerhouse in Mouth of Wilson, Va. In summer 2010, shortly before Cook arrived at Oak Hill for his senior season, Durant took a break from training camp with Team USA to share his experience as a high-profile recruit.

It was the trust he had in Texas head coach Rick Barnes that made him sign with the Longhorns four years earlier, Durant told Cook. A top-25 prospect nationally at the time, Cook signed with Duke months later for the chance to play under Mike Krzyzewski.

Cook grew increasingly frustrated while buried on the Blue Devils’ bench as a freshman. After games that season, he often checked his iPhone to find text messages from Durant: “Don’t let them see you sweat;” “Body language is everything;” “Be a pro.”

In summer 2013, after starting 34 of 36 games as a sophomore, Cook flew to Oklahoma City to train with Durant. Those workouts helped set the foundation for Durant’s 2013-14 NBA MVP season. Less than a year after the man he calls a “big brother” won the sport’s top individual honor, Cook guided Duke to its first national title in five years.

“Kevin knows how much I look up to him,” Cook said. “I always thank him for being the best role model I could have.”

Cook has made the most of his professional opportunities. After not hearing his name called in the 2015 NBA draft, he was named D-League Rookie of the Year. His per-36-minute averages in 15 NBA games — 15.4 points on 50.7 percent shooting and 5.0 assists — suggest he can play at that level.

However, many front offices view him as a three-point specialist who lacks NBA athleticism and struggles to defend elite guards. Cook signed a training camp deal this past summer with the Hawks, only to be one of the team’s final preseason cuts.

Last Monday, Cook was relaxing at his Atlanta apartment when his agent called to tell him that Cook had 30 minutes to decide whether to sign a two-way deal with Golden State. It took less than 30 seconds for Cook to give his answer and start stuffing his luggage.

As Cook waited to board his flight to Oakland, he chatted with Durant on FaceTime about how far they’ve come — from the PG Jaguars’ pipeline to the roster of a defending NBA champion.

“I was so excited, man, especially for him,” Durant said. “I know how hard he’s worked. I’m just happy we’re going to be doing life together and playing in the NBA together. It’s a dream come true for both of us. It’s amazing.”

Connor Letourneau is a San Francisco Chronicle staff writer. Email: cletourneau@sfchronicle.com. Twitter: @Con_Chron