Joe Lhota’s day has come and gone – again.

Lhota, who took on the enormous task of fixing the crumbling subway last year despite a high-powered job at NYU Langone and a handful of board positions, resigned as chairman of the MTA on Friday.

Fernando Ferrer, the transit agency’s vice chairman, was named acting chair effective immediately, MTA officials revealed.

Lhota, 64, was named chairman in the summer of 2017 amid a crisis of repeated subway breakdowns. But he agreed to do the job on a part-time basis, only taking on the chairman role but not the CEO role while remaining chief of staff at NYU Langone Medical Center.

Lhota said in a statement that he took on the position for the “sole purpose of halting the decline of service and stabilizing the system for my fellow New Yorkers.”

“When I agreed to return to the MTA it was with the understanding that I would maintain my private sector positions and delegate day-to-day responsibility to a new team,” he said in a statement. “Accordingly, I created the Office of the Chairman for the purpose of managing the MTA.”

Lhota, who had previously run the MTA from 2012 to 2013, hit the ground running in 2017, implementing a wide-reaching $836 million action plan to stem delays that included ripping out seats to fit more riders, buying massive vacuum trains to suck the trash from tracks, and adding more EMTs to more quickly deal with sick passengers.The plan has had marginal successes at cutting down on delays. On Friday, the MTA immediately followed up notice of Lhota’s resignation with the latest subway data, which shows that weekday on-time performance increased to 70 percent for the first time since August of 2015.

Lhota’s departure came as a surprise for many. He played coy just last month when asked if he planned to leave his post.

“My term ends on June 10, 2021,” he told a group of gathered reporters.

MTA board members called a Lhota a formidable manager and politicians who helped put the spotlight on the subway system’s many weaknesses and brought in a crack team of new leaders – including British subway wonk Andy Byford- to help rejuvenate the agency.

“Joe was a great friend and advocate for the transit system and he’s going to be sorely missed,” said board member Mitchell Pally. “He brought tremendous direct attention to the inadequacies of the system from a financial standpoint and maintenance standpoint.”

Others, who had railed against Lhota’s overstuffed schedule and conflicts of interest, were happy to see him step down.

“The Chairman and CEO of the MTA has historically been one person’s one and only job, and that’s to focus on serving the interests of the public alone,” said Susan Lerner, who is executive director of Common Cause New York, which had called for an ethics investigation into Lhota. “It is a clear conflict of interest and a violation of the spirit of the public officer’s law, for the MTA Chairman to serve several masters.”

Gov. Andrew Cuomo issued a statement praising Lhota for coming back a second time to help fix transit service.

“Joe Lhota has dedicated decades of his life to public service culminating in two tours of duty at the helm of the MTA. He stabilized the subway system, appointed a new leadership structure to completely overhaul the MTA, and led with a steady hand during some of the agency’s most challenging moments.” the governor said in a statement.

“In short, Joe demonstrated time and again why he was the right person for the job. I am deeply grateful for his service to the State of New York.”