London was born in The Bronx, but grew up in Flushing, Queens, before moving to Los Angeles in his adult years.
His signature line is "You might recognize me, I'm the fourth guy from the left on the evolutionary chart," referring to his slouching posture and unkempt appearance.
During his run on Last Comic Standing, he made a guest appearance on The Tonight Show with Jay Leno.
In 2004, Jay made an appearance on the game show Street Smarts; in 2005, he appeared on the CBS sitcom The King of Queens, on the TBS reality show Minding the Store and Bravo's All-Star Reality Reunion.
On August 1, 2006, Mr. London made a return appearance on Last Comic Standing.