The newly added show will be on Dec. 19 at the NYCB Theater in Westbury. He and fellow comedian Colin Quinn, who is touring with the "Seinfeld" star, will donate all proceeds to groups helping storm victims.
Both will also donate all revenue from Thursday's show in Brooklyn and a Dec. 6 show in Staten Island.
"I grew up on Long Island, and New York City is home," Seinfeld said in a statement. "This is a tough time for this area, and we're just glad to be able to help in the recovery."
Seinfeld's tour kicked off Oct. 4.