Alfred Portale, the chef whose name has been synonymous for 34 years with Gotham Bar and Grill, a mainstay near Union Square, is no longer in the kitchen there. He has been replaced as executive chef by Victoria Blamey, who rose to prominence as the executive chef at Chumley’s, in the West Village, from 2016 to 2017.

Mr. Portale, who plans to open his own restaurant, Portale, this fall in Chelsea, left the job several weeks ago, after his business partners — Jerome Kretchmer, Jeff Bliss, Robert Rathe and Richard Rathe — decided to change the direction of the restaurant.

Mr. Portale, 65, took charge of the kitchen in 1985, a year after Gotham opened, and remains a partner. In an interview on Tuesday, he said that discussions about updating the restaurant began a few years ago. “At first I was involved in the process,” Mr. Portale said. “But finally, it did not happen the way I would have liked it to.”