With the continuing success of "The Simpsons", Azaria began taking on other, principally live-action, roles. He was a main cast member on the show "Herman's Head" (1991–1994) playing Jay Nichols, alongside "The Simpsons" co-star Yeardley Smith. He regularly recorded for "The Simpsons" and filmed "Herman's Head" during the same day. Following the series' cancellation Azaria unsuccessfully auditioned for the role of Joey Tribbiani, one of the lead characters in the sitcom "Friends". He was instead cast in the role of the scientist David, one of Phoebe Buffay's boyfriends in the series. He appeared in the show's tenth episode "The One with the Monkey", before the character left for a research trip in Minsk. He reprised the role in the show's seventh season (2001), before making several appearances in the ninth (2003). This return culminates in David proposing to Phoebe; she rejects him, and David leaves the show for good. From 1995 to 1999, Azaria had a recurring role in the sitcom "Mad About You" as Nat Ostertag, the dog walker. Azaria was nominated for the Primetime Emmy Award for Outstanding Guest Actor in a Comedy Series for his roles in both "Mad About You" (in 1998) and "Friends" (in 2003). Azaria had the lead role in the short-lived sitcom "If Not For You" in 1995, playing record producer Craig Schaeffer.