John Pinette, the portly stand-up comedian who portrayed a hapless carjacking victim in the final episode of “Seinfeld,” died April 5 at a hotel in Pittsburgh. He was 50.

The Allegheny County Medical Examiner’s office confirmed the death. His manager, Larry Schapiro, told the New York Times that the apparent cause was a pulmonary embolism.

Mr. Pinette was a self-deprecating presence on stage, frequently discussing his weight on stand-up specials “Show Me the Buffett,” “I’m Starvin’!” and “Still Hungry.”

He once quipped about his gym regimen: “I lost 100 pounds, and people say to me, ‘Wow, we can really see it in your face.’ ”

He was also known for his signature line, “I say, ‘Nay-nay!’ ” which he often used as he recounted his efforts to diet and his aversion to salad. He also underwent gastric bypass surgery.

Comedian John Pinette addresses the crowd during the 2008 NASCAR Sprint Cup Series Awards Ceremony in New York. (Lucas Jackson/Reuters)

John Paul Pinette was born March 23, 1964, in Malden, Mass. He graduated with an accounting degree in 1986 from what is now the University of Massachusetts at Lowell.

He lasted six months in that career.

“I knew the book theory but I didn’t have the heart for it,” he told the Montreal Gazette. “I did it for six months and my job was to distract the auditors with jokes.”

He immersed himself in Boston’s busy comedy scene and was opening for Frank Sinatra within six years. More prominent stand-up dates followed, along with appearances on early 1990s television shows such as “Parker Lewis Can’t Lose.”

Mr. Pinette also appeared on stage in a national tour of “Hairspray” as Edna Turnblad, the mother of the play’s heroine.

He had supporting roles in movie such as “Simon Sez” (1999), which starred Dennis Rodman, and “The Punisher” (2004), which featured Thomas Jane.

Mr. Pinette had a trio of stand-up shows released on DVD but was perhaps best known as the carjacking victim whose plight lands the “Seinfeld” stars before a judge for failing to help under a “good Samaritan” law.

Last August, Mr. Pinette reportedly entered a rehabilitation facility for prescription drug addiction.

Survivors include a brother and two sisters, the Times reported.

— Associated Press