After working in Paris as a scent designer for Lanvin, Gertz returned to the United States and landed a key supporting role in the 1996 blockbuster Twister after other films including 1986's Solarbabies and Crossroads, the 1989 film Listen to Me with Kirk Cameron, The Boyfriend School, and Jersey Girl. In the 1994 episode of Seinfeld, "The Stall", she appeared as one of Jerry's girlfriends who works as a phone sex operator and can't "spare a square" of toilet paper to Elaine in the restroom. Also in 1994 she played Sarah in the TV movie This Can't Be Love starring Katharine Hepburn, Anthony Quinn, and Jason Bateman. Gertz later played the recurring character Dr. Nina Pomerantz during the 1997 season of ER. She reportedly was offered, but declined, the role of Rachel Green, during pre-production of Friends.