Welker portrayed the characters Jorak Uln, Sunry, and Handon Guld in Star Wars: Knights of the Old Republic.
In 1980, he voiced Mr. Cool in the animated series The Fonz and the Happy Days Gang, alongside Ron Howard.
As of July 2011, Welker has voiced or appeared in ninety-six motion pictures with a combined gross revenue of over 6.2 billion dollars. No other actor's filmography has collectively earned more; Welker sits at the number one position in The Numbers.com's "All Time Top 100 Stars at the Box Office" list. Other Star Wars actors on the list are Samuel L. Jackson (#2), John Ratzenberger (#4), Harrison Ford (#6), Warwick Davis (#7), James Earl Jones (#14), Frank Oz (#33), Liam Neeson (#40), Kenny Baker (#52), Christopher Lee (#55), Anthony Daniels (#74), Jon Favreau (#82), and Natalie Portman (#94).
- Star Wars: Galactic Battlegrounds
- Star Wars: The Clone Wars (video game)
- Star Wars: Knights of the Old Republic
- Star Wars Resistance — "The Children from Tehar"
- Star Wars Resistance — "Bibo"
- Star Wars Resistance — "The New Trooper"
- Star Wars Resistance — "Descent"
- Star Wars Resistance — "No Escape: Part 2"
- Star Wars Resistance — "Into the Unknown"
- Star Wars Resistance — "The Mutiny"