Jay Scott Greenspan (born September 23, 1959), known professionally as Jason Alexander, is an American actor, comedian, host and director. An Emmy and Tony winner, he is best known for his role as George Costanza in the television series Seinfeld (1989–1998), for which he was nominated for seven consecutive Primetime Emmy Awards and four Golden Globe Awards.
His other roles include Phillip Stuckey in the film Pretty Woman (1990), comic relief gargoyle Hugo in the Disney animated feature The Hunchback of Notre Dame (1996), and the title character in the animated series Duckman (1994–1997). He has made guest appearances on shows such as Dream On (1994), Curb Your Enthusiasm (2001, 2009), and The Marvelous Mrs. Maisel (2019). For his role in Dream On, he was nominated for a Primetime Emmy Award for Outstanding Guest Actor in a Comedy Series. He won the Daytime Emmy Award for Outstanding Original Song for "The Bad Guys?" on Brainwashed By Toons (2020).
Alexander made his Broadway debut originating the role of Joe in Stephen Sondheim's Merrily We Roll Along in 1981. He remained active on Broadway acting in the musicals The Rink in 1984, Personals in 1985, and the Neil Simon play Broadway Bound in 1986. He then starred in Jerome Robbins' Broadway in 1989, for which he won the Tony Award for Best Actor in a Musical. He appeared in the Los Angeles production of Mel Brooks' The Producers. He was the artistic director of "Reprise! Broadway's Best in Los Angeles", where he has directed musicals. From July 2023 he will make his Broadway directing debut with Sandy Rustin’s comedy The Cottage. The cast includes Eric McCormack, Laura Bell Bundy and Lilli Cooper.Source : Wikipedia