Season 3 of Seinfeld premiered on 1991-09-18. The first episode of the season was filmed around 1991. Here are the cast ages at the time of filming.
| Actor | Character | Age at Filming | Birthplace | Also Known For |
|---|---|---|---|---|
| Jerry Seinfeld | Jerry Seinfeld | 37.2 years | Brooklyn, NY | Stand-up comedy, Bee Movie |
| Jason Alexander | George Costanza | 31.8 years | Newark, NJ | Stage actor, Pretty Woman |
| Michael Richards | Cosmo Kramer | 42.0 years | Culver City, CA | Stand-up comedy |
| Julia Louis-Dreyfus | Elaine Benes | 30.5 years | New York, NY | Veep, Saturday Night Live |
Jerry Seinfeld was approximately 37.2 years old when Seinfeld Season 3 was filmed around 1991.
Jason Alexander was approximately 31.8 years old when Seinfeld Season 3 was filmed around 1991.
Michael Richards was approximately 42.0 years old when Seinfeld Season 3 was filmed around 1991.
Julia Louis-Dreyfus was approximately 30.5 years old when Seinfeld Season 3 was filmed around 1991.
Keith Hernandez appeared as guests in Season 3.
| Celebrity | Appeared As | Episode | Age at Filming | Known For |
|---|---|---|---|---|
| Keith Hernandez | Himself | The Boyfriend (Part 1) (S03) | 38.1 years | The Yards, Law & Order |
Yes — Keith Hernandez appeared in Seinfeld in the episode "The Boyfriend (Part 1)" (Season 3), playing Himself.
Keith Hernandez was approximately 38.1 years old (38) when their scene in "The Boyfriend (Part 1)" was filmed around 1991.