Three of the most popular projects that he has been involved with were two Steven Spielberg films, Duel and Close Encounters of the Third Kind, and the Westwood Studios computer game Command & Conquer: Red Alert.

In Command & Conquer: Red Alert, Dynarski plays a major supporting role as Soviet Premier Joseph Stalin, appearing throughout much of the game's Soviet campaign and, to a lesser extent, the Allied campaign.

In the 1974 film Earthquake, Dynarski portrays Fred, a worker at the Mulholland Dam who becomes the first fatality of the disaster.

He was one of 32 actors or actresses to have guest-starred in both the original Star Trek television series (episodes "Mudd's Women" and "The Mark of Gideon") and in one of the series' spin offs (Star Trek: The Next Generation's "11001001").

Dynarski is also known for his two appearances as Izzy Mandelbaum Jr. on Seinfeld and as Helmut Jitters in the short film Apple Jack.