At first, he was just Mr. Leftwich, a man with a grandfatherly aura who held the keys to the athletic office at Carroll High as the school’s athletic director.

Then one day last year, Justin Milstead took a closer look at the trophy case, his eyes scanning the names and faces of the grainy black-and-white basketball team photos. There, among a collection of talent that won 55 consecutive games, two city titles and a place within basketball lore, was George Leftwich, living legend.

“Once I saw his picture, I was like ‘Oh wow, that’s him,’ ” said Milstead, a rising sophomore guard at Carroll. “I started going to his office and talking to him with some of my teammates, and he’d tell us all the stories and I realized how much he had done.”

The tales spanned more than 50 years of playing and coaching basketball, beginning with his starring role on one of the area’s first integrated high school teams and culminating this past winter, when the 72-year-old was called upon to lead the Lions following a late-season coaching change.

After spending the past eight years as athletic director at Carroll, Leftwich will retire at month’s end.

In this 1960 file photo, players from Carroll’s basketball team celebrate their 55-game winning streak by showing off trophies from the Eastern States Catholic Invitation tournament. From left are Lee Lindsay, John Austin, Larry Rohan, George Leftwich, John Thompson Jr., Chuck Rohan, and Walt Skinner. (Jim McNamara/THE WASHINGTON POST)

“I guess they squeezed a little bit more coaching out of me in the end,” a chuckling Leftwich said recently while cleaning out his office. “But it’s time to step aside and let the younger generation take over. I’ve had a great run. I’ve had fun and that’s why I’ve stayed so long. But now it’s time for a change.”

Initially, the fun came at Leftwich’s expense. With no courts near his childhood home in Northwest, Leftwich didn’t pick up a basketball until seventh grade, when his classmates jeered him for not knowing how to play.

“That was a little more than my ego could take, so that whole summer I didn’t play any other sport but basketball,” Leftwich recalled. “After that, I just stayed with it and started playing with the bigger guys who used to beat me up a little on the court.”

By the time he enrolled at Carroll as a 10th-grader, Leftwich had developed a sweet stroke from the perimeter and a quick first step, leading the Lions to the 1958 City Title Game, where they fell to Cardozo.

The loss morphed Leftwich’s approach to the game. For as talented as the Lions were, boasting the likes of future NBA players John Thompson Jr. and Tom Hoover and former Notre Dame president Edward “Monk” Malloy, none of the other four starters could handle the ball.

Leftwich became the Lions’ playmaker in 1959, beginning a historic win streak that spanned two seasons and included victories against several college freshman teams.

“George was an extremely smart player, which was helpful for me because he taught me how to think the game,” Thompson said. “He could shoot like hell, and I’ve never been around anybody who wanted to win as much as he did.”

George Leftwich is photographed going through a scrapbook at his home in Silver Spring. Leftwich is on the far right of the newspaper clipping honoring The Post’s 1960 All-Met basketball team. (Ricky Carioti/WASHINGTON POST)

Leftwich’s success continued at Villanova. He helped lead the Wildcats and their renowned zone defense to two wins in the 1962 NCAA tournament. By most accounts, Leftwich appeared on his way to the NBA until a car accident that following summer.

While on a trip to West Virginia, an oil truck sideswiped his car, sending Leftwich out the door and into the street, badly injuring his knee.

Doctors recommended an exploratory operation, but Leftwich had his doubts.

Surgery was not as advanced at the time and he learned that a man had recently died from a similar procedure. So Leftwich elected to let his knee heal naturally, effectively ending his shot at the NBA.

“To be good, you’re only a step faster than the pack, and once I hurt my knee, I lost a step,” Leftwich said. “At the time, the NBA wasn’t paying big money and teams were still riding on buses, so I said no. But if it had happened today, I would say ‘Cut me!’ ”

After helping the Wildcats to the 1965 National Invitation Tournament title game, Leftwich eventually became the varsity coach at Carroll in 1968, which was the same year he married his wife, Mary.

Along with raising two sons who would go on to play at Princeton, Leftwich developed several basketball minds, including former Washington Wizards head coach and newly hired Rutgers Coach Eddie Jordan, who played for Carroll in the ’70s, and Sidwell Friends Coach Eric Singletary, who played under Leftwich in the first of his 13 seasons at Sidwell. In between, Leftwich led Gwynn Park to Maryland state titles in 1987 and 1988.

“He was demanding, but he was patient and a great teacher,” Singletary said. “He taught us tenacity and preparation to where we always thought we had a shot, no matter who we played.”

Those lessons served as the foundation for Leftwich’s brief tenure this past February, when he took over Carroll’s varsity team following the sudden resignation of Reggie Williams.

With three games remaining and just two wins to their credit, the Lions were running low on resolve.

With his belief that the key to coaching is a love for kids, Leftwich bought the team warmup shirts and arranged a pregame meal, striking a balance of respect and fun that propelled the Lions to their lone Washington Catholic Athletic Conference win.

“He always stayed positive and motivated us, and we believed in him because we knew he believed in us,” Milstead said. “We told him after the last game how glad we were that he coached us. We learned a lot in a short time.”