Also in the episode he is repeatedly harassed by a man named George – his character's name on Seinfeld. In 2007 Alexander appeared in a commercial for the ASPCA which has aired on cable TV stations. Alexander starred in A Fairly Odd Movie: Grow Up Timmy Turner! as Cosmo.
He also has had an active career on the stage appearing in several Broadway musicals including Jerome Robbins' Broadway in 1989 for which he won the Tony Award as Best Featured Actor in a Musical. He is the Artistic Director of "Reprise! Broadway's Best in Los Angeles" where he has directed several musicals.