Retired NYPD Officer Steve Dillon climbed the mound at Citi Field to play in the Old Timers game last month — his first time donning a Mets uniform since the 1960s.

Dillon, now 79, played for the Mets from 1963 to 1965 before taking on his second calling as a New York City police officer.

“When I walked into the clubhouse, it was like old-home week,” the southpaw former cop told The Post of playing in the nostalgic annual game Aug. 27.

“[Former outfielder] Ron Swoboda teased me. He said, ‘Hey, Lefty, don’t throw those meatballs.’ ”

Dozens of Dillon’s relatives were in the stands to cheer him on the field, including his son Steve Dillon Jr., who shares not just his father’s name but membership in the same two exclusive New York City institutions — the NYPD and the Queens ball club.

“I was so proud of my father,” said the younger Dillon, who now works as the senior director of security for the Mets after retiring from the NYPD as a detective with the Emergency Service Unit. “I never saw him pitch [before Saturday].”

The elder Dillon spent a year on a Yankees farm team fresh out of Cardinal Hayes High School before joining the Mets in 1963.

He ended up pitching the first-ever night game at Shea Stadium, as the final reliever in what would be a loss to the Cincinnati Reds.

But when the Mets roster shrunk in 1965, Dillon got sent back to the minors and left baseball soon after. In 1969, he became a New York City police officer.

“I remember some of my friends said they were going to take the police test, so I went, and 11 months later, I got a call,” Dillon Sr. said.

The job — then as now — was a pay cut from major-league ball, but the work was fulfilling, he said.

“I loved being a cop. Every day was different,” the elder Dillon said. “I loved helping people. That was rewarding, also. The people respected you, not like today. I wouldn’t want to be a cop today.”

Getting back on the baseball field was a dream come true, said Dillon, who was the oldest to play for the Mets at this year’s Old Timers Day.

“I trained for a couple of months for [the game], I didn’t want to embarrass myself,” he said. “I think the training paid off.”

Dillon Sr. pitched to Mookie Wilson and Daniel Murphy.

The younger Dillon said fans still mail his ex-Met dad baseball cards asking for an autograph.

“Someone said it was worth $17.95,” Dillion Jr. said of a card signed by his pop.

“But it might have gone up after [last month’s game],” the son quipped.

The younger Dillon followed his father into police work, attracted by the camaraderie of the job.

“I guess I became a cop because of my father,” he said. “I remember going to visit him in the precinct and sitting in the radio car, going to his precinct softball games.”

Dillon Jr. inherited his dad’s allegiance to the Mets, too.

“I grew up a Met fan, and now I travel with the team and work for a great owner,” the son said. “This is a great job.”

But the Dillons weren’t the only ones at the event with ties to both the Mets and the NYPD.

Jesse Orosco, the famed pitcher who helped secure the Mets’ 1986 World Series win, threw at the Old Timers game as well.

And asked afterward by a reporter what happened to the glove he threw in the air after the 1986 win, Orosco recalled that he gave it to a New York City cop who’d been shot, hoping the badly wounded Finest could sell it to help cover medical bills.

That cop was Steven McDonald, who was left paralyzed when he was shot three times at close range while questioning a robbery suspect in July 1986.

The hero cop’s son, NYPD Lt. Conor McDonald, told The Post that the glove stayed in the family — with his father keeping it in a glass display case in his room until he died in 2017.

“He talked about the glove a lot. He was very grateful,” McDonald said of his father. “He still followed the Mets and would love the year that they are having.

“One of the last things my father did before he was shot was to attend the Mets game the night of July 11, 1986 — the night before he was shot,” McDonald said. “To watch his team win it all while fighting for his life in Bellevue Hospital after he was shot helped him get through some of the toughest nights of his life.

“The Mets and [hockey’s New York] Rangers were his teams. They brought him a lot of joy,” he added.

Orosco added to The Post, “People always ask me why did I give the glove away, but I have no regrets giving officer McDonald that glove.

“I am glad that it made him happy — that makes me feel good.”