The Fat Cat union president exposed by The Post last week for sleeping on the job and scarfing down thousands of dollars in food on the rank-and-file’s dime was pushed from his cushy perch last night in a landslide vote.

Mark Rosenthal — a 400-pound labor heavyweight who had run municipal-workers union Local 983 for 15 years — was trounced by his challenger, Joseph Puleo, in a 371-165 vote.

Rosenthal seemed confident before the ballots were tallied, but was left stunned by the result.

“No, I’m sorry,” he said by phone, after sneaking quietly away from the polling place when it became clear the election was going against him. “I don’t have anything to say.”

His challenger, meanwhile, trumpeted his victory as a new era for the union.

“Local 983 now has democracy and we have a lot of work ahead,” said Puleo, who had formerly been a vice president at the 3,000-member union.

Many union members told The Post they voted for Rosenthal’s challenger because they were fed up with the way the sleepy president was running the shop.

“We’ve got to get Rosenthal out of there. No more fat cat,” said a Parks Department worker who arrived at the West Side polling place with The Post’s May 28 front-page story taped to her car window.

“Mark’s been sleeping for too long,” said Charles St. Louis, 49, a city Parks peace officer. “We want him out. The fat cat has been sleeping, and we’re going to wake him up today.”

Rosenthal routinely fell asleep at his desk in the union office after downing a huge meal.

He slumbered — with a soda sitting on his desk — even as he collected $156,000 a year in salary from dues paid by some of the city’s lowest-paid workers.

He also was accused of running up bills as high as $1,400 a month on food — all on the union’s tab.

The vote ended a heated race for the union’s top job.

“I’m surprised how dirty it got. I’ve known Mark for years and didn’t think it would get that bad,” Puleo said before the results were tallied.

Both sides had filed lawsuits over various disagreements.

In addition to his heavy eating and napping habits, NYPD tow- truck drivers last month blasted Rosenthal for being AWOL during Hurricane Sandy as their private cars were flooded.

He also made news when he inspired a City Council bill for oversized ambulances after he suffered a stroke at City Hall.

And he claimed ignorance when The Post confronted him over the fact that the FBI raided his house and slapped his roommate with drug charges for allegedly cooking meth right under his nose.