At long last, the Mets’ search for a top baseball executive is finally over.

Billy Eppler and the Mets were finalizing an agreement Monday night to make him their next general manager, The Post’s Joel Sherman reported, putting an end to a winding search that lasted six weeks and struggled to attract many top candidates along the way.

Eppler, 46, most recently served as general manager of the Angels for five seasons before being fired last year. In September, the William Morris Endeavor agency hired Eppler as a co-leader of its new baseball representation business.

Prior to the Angels, Eppler worked for the Yankees from 2004-15, becoming their director of professional scouting in 2005 and then being promoted to assistant GM during the 2011-12 offseason as one of Brian Cashman’s top lieutenants.

“I think Billy’s fantastic,” Cashman said last week at the GM meetings. “Anybody who knows me knows my relationship with him. I was lucky to have him working with us. He guided us greatly. I know how good Billy really is. … His name should pop into anything that pops up. He’s that talented.”

During his time with the Angels, Eppler’s biggest feat was signing two-way star Shohei Ohtani. But he was unable to sufficiently build a team around Ohtani and co-star Mike Trout, recording losing seasons in all five years he was at the helm in large part due to a lack of quality starting pitching.

Last week, former Nationals assistant GM Adam Cromie had emerged as the front-runner for the Mets’ GM job. But the interest had seemingly cooled since then, with Cromie being out of baseball since 2017 to work as an attorney.

Eppler’s hiring brings an end to a process that began aiming high — with Theo Epstein, Billy Beane and David Stearns targeted as candidates to become the club’s president of baseball operations — before the Mets settled for hiring a GM for the second straight offseason. They again ran into a number of challenges, from not getting permission to interview other teams’ executives to other candidates withdrawing from consideration for various reasons.

Looming over the hire is the potential for the Mets to make another run at Stearns next offseason. The Brewers declined the Mets’ request to interview him this offseason, as he is under contract as Milwaukee’s president of baseball operations through at least 2022, but his status beyond that remains unclear.

For now, Eppler will take over GM duties from team president Sandy Alderson, who had been running baseball operations since acting GM Zack Scott was placed on administrative leave in September following pleading not guilty to a DWI charge. Scott had been elevated into the job when Jared Porter, who was hired as GM to end last year’s search, was fired after it was revealed he had sent lewd text messages to a female reporter.

“Assuming we only hire one person, there will be at least a year’s runway for that person to demonstrate their ability and their potential,” Alderson said last week. “I’ve said this to others in the past, that’s the opportunity. That’s all you can ask for. And demonstrated ability tends to get rewarded.”

With the Mets, Eppler will be tasked with hiring a manager and filling out almost an entire coaching staff. He hired two managers while leading the Angels, Brad Ausmus and Joe Maddon, but also hired Mickey Callaway as Maddon’s pitching coach after the Mets fired him as manager in 2019. The Angels ultimately suspended Callaway last February, when The Athletic reported that at least five women had accused him of sexual harassment, before MLB banned him in May through at least the 2022 season.

Eppler will also have less than two weeks to dive into player personnel decisions before a potential work stoppage — which would freeze player transactions — with the collective bargaining agreement set to expire at midnight Dec. 1.