(written from a Production point of view)
Mal Friedman (born 15 September 1935; age 86) played redshirt Hendorff in the Star Trek: The Original Series second season episode "The Apple". He filmed his scenes on Monday 17 July 1967 at Desilu Stage 10.
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. (Starlog Magazine Issue 283, p. 61)
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.