(written from a Production point of view)
Besides acting in children's theatre and in smaller roles on stage, Friedman worked as carpet cleaner, and was also employed by Gene Coon's wife, who brought him to the attention of her Star Trek producer husband, which resulted in his short guest spot in the series. (These Are the Voyages: TOS Season Two)
This is currently his only known acting role in either television or film. However, he did lend his voice to the 1995 video game Full Throttle, as did Star Trek: Deep Space Nine guest actor Hamilton Camp.