Kevin Gilbride strolls off of the pebbly green turf inside Superdome Sports in Waldwick, N.J., ceding the practice field to a group of young girls arriving at lacrosse practice on this December afternoon.

To his right, a set of taped yellow field goal posts hang on an inflated wall. Above him in the same building is a ballet studio and something curiously named “Music For Aardvarks.” And roughly 25 minutes down Route 17 is MetLife Stadium, Gilbride’s former home with the Giants.

Gilbride may be near his ex-team, but he’s a virtual world away from the heights of the NFL.

After his exit from New York six years ago, the 68-year-old has returned to coaching again with the XFL’s New York Guardians, agreeing in April to be their head coach and general manager. He returns to MetLife this weekend, with the Guardians set to play their home games in East Rutherford for the revamped XFL’s inaugural season.

“I think it was a lot of things,” Gilbride said of this return to football. “I jokingly said my oldest granddaughter started finishing my stories. I knew I had to either create new stories or get a new audience.”

Gilbride stayed occupied during his retirement.

Dividing his time between Florida and Rhode Island, where his daughters Kelly and Kristen live (along with his grandchildren), the former Giants coach settled into a relaxing routine. Gilbride hung out with his beloved five grandchildren (ages 15, 11, 9, 3 and 1), dug into his large collection of his books and enjoyed some fishing days on his boat.

Virtually every night ended the same way, with Gilbride and Deborah, his wife of 45 years, watching “Wheel of Fortune” over dinner at 7 p.m.

“If we really had a long dinner, it went into ‘Jeopardy!,’ too,” Deborah said.

Gilbride made up for lost time during this period, reconnecting with old friends and fully reintegrating himself into family life after living in a hotel for the last five years of his Giants tenure.

Deborah calls their grandchildren “the sparkle in our eyes,” but Gilbride never veered too far from his other love either.

He maintained a steady diet of film by contributing to NBC’s “Sunday Night Football” preparations, keeping his eye for X’s and O’s sharp (his son, Kevin, was also a coach with the Giants and the Bears during this time).

That sort of work was enough to keep Gilbride — now with his eighth pro football franchise — up to date on the game and its latest developments. But it was far from enough to whet his coaching appetite.

“When you’re at home watching football, sitting around putting another piece of popcorn in your mouth, you’re watching everybody else, but you miss the players, the camaraderie,” Guardians running backs coach Jerald Ingram told The Post.

“You’re always [saying] as a coach, ‘I can do that better. I know I can be better as a coach.’ ”

Gilbride undoubtedly loves football — he initially refused to take time off from the sport after a cancer diagnosis in 1992 while serving as the Oilers’ offensive coordinator.

But what he really loves — what he missed during his retirement — was leading a group of young men. Analyzing plays from home could never replicate the human element of instruction.

“For me to tell Cris Collinsworth what’s going on — that’s nice, it’s fun,” he said. “But it’s not the same as coaching.”

Tracing Gilbride’s return to coaching extends far beyond recent history.

Sure, he hasn’t forgotten about having to live in a “one-room Residence Inn” and going months without seeing his grandchildren. The Guardians job is convenient — he’ll be near his family in Rhode Island and Connecticut — but convenience isn’t the only thing luring him back to the sport on a full-time basis.

The former Giants quarterbacks coach and offensive coordinator (2004-13) — who also led elite offenses with the Oilers and Jaguars — got just one chance in his career to lead a team.

He was handed the reins to the Chargers for a short stint from 1997-98, yet the tenure spanned just 22 games and netted six wins. He told The Post it was “a mess.”

Gilbride thought he would finally be offered another head-coaching job following his second Giants Super Bowl win in 2012, but that offer never came and he was forced out of the franchise following the 2013 season, The Post reported at the time. Now, the XFL is giving him the opportunity he has long craved to build a team.

“It’s not the NFL,” he said. “But you get a chance to put your stamp on all parts of it.”

Gilbride has been a chameleon of sorts in his coaching career. Known for pass-heavy attacks in Jacksonville and Houston, he molded a more balanced offense at Tom Coughlin’s direction in New York.

Even with star wideouts Plaxico Burress, Hakeem Nicks and Victor Cruz, the Giants never veered too far from the run game en route to their two Super Bowls with Coughlin.

That was more Coughlin’s identity revealing itself than Gilbride’s. From 1990-96, Gilbride led the NFL’s No. 1 passing offense four times — three times with the Oilers and once with the Jaguars. He never once achieved the same feat with the Super Bowl-winning Giants.

Now, Gilbride gets another chance to win and lose on his own terms.

“We’ll try to do some things that you wouldn’t see with the Giants,” he said.

There’s an obvious irony in the fact Gilbride will be resuming his coaching career at MetLife, the site of some of his greatest coaching achievements, but also his unceremonious exit from the NFL.

With time, the fans who used to call him “Kevin Killdrive” may have grown to appreciate his contributions. He even says he’ll get calls now from people telling him of rekindled praise in the area.

“People all the time had these nicknames for him,” former Giants running back Brandon Jacobs told The Post. “They was outside the building. They was outside of the walls.”

Such is the dichotomy that surrounded Gilbride throughout much of his Giants stint: admired by many of the game’s important figures and reviled by many of the home fans.

Tom Brady was one such admirer. Back at the old Giants Stadium in 2007, Brady was nagging Gilbride.

The Patriots had just defeated the Giants in a 38-35 thriller in Week 17 to cement their regular perfect 16-0 regular season. But Brady wasn’t so interested in celebrating after the game, instead trying to gain some intel from Gilbride, who was then in his first season leading the Giants’ offense.

“What was that play you guys were running?” Ingram, who coached the Giants running backs from 2004-13, remembers Brady saying at the time. “That was kinda neat.”

The exchange, in which Gilbride declined to give Brady anything, is an apt representation of Gilbride’s stature within the sport. Jim Hermann, the Guardians’ defensive coordinator who was the Giants’ linebackers coach from 2009-15, sides with Brady.

“The true people that know the game of football … I think he’s probably very well appreciated.”

As Gilbride floated around the Guardians’ practice in a black hoodie and black sweats, he looked at home in the head-coaching role he’s sought for so long. He didn’t say too much during the session, often allowing his coaches to do the micromanaging as he chomped down on chewing gum. Yet he made his presence felt and voice heard when necessary.

Gilbride’s résumé speaks for itself. A pro coaching career that began in 1985 has yielded two Super Bowls and numerous productive offenses.

Still, there have been doubters and detractors, especially at his most recent stop. Gilbride has decided to test himself yet again, in the shadow of his previous employer.

“He’s gonna remember [his exit from New York],” Jacobs said. “He was told he couldn’t do something.”