Part of Seinfeld featuring Jerry Seinfeld, Julia Louis-Dreyfus, Michael Richards, Wayne Knight, and Larry David.
Rise to Fame
He was already a Tony winner when Seinfeld came calling. Won Best Actor in a Musical in 1989 for Jerome Robbins' Broadway, playing multiple roles in a single show (Tevye, Pseudolus, among others). That same year, he got the George Costanza role by doing a Woody Allen impression at a casting call that specifically sought theater actors. George was partly based on Larry David, which made the character feel like comedy's sharpest self-portrait.
In the Spotlight
After Seinfeld ended in 1998, Alexander moved toward directing. The Cottage on Broadway in 2023 was his project. He voiced a recurring character on Star Trek: Prodigy across 23 episodes between 2022 and 2024. The Seinfeld reunion people wanted finally happened in a Curb Your Enthusiasm storyline in 2009, which tells you how far that show's grip extends. Seven Emmy nominations during the original run and zero wins remains one of television's more durable punchlines.
Side Notes
The Magic Castle named him parlor magician of the year in 2006. He's a genuine poker player too: made it to day 3 of the World Series of Poker main event in 2009 and won the Celebrity Poker Showdown finale, banking $500,000 for the United Way. He attended Boston University's School for the Arts and his birth name is Jay Scott Greenspan. The Tony came at 29. Seinfeld premiered the following month.