Trivia

Of Puerto Rican descent, Sierra feigned a noticeable accent in Barney Miller (1975) and Sanford and Son (1972). However, in other appearances, including Infierno en la torre (1974) and the All in the Family (1971) episode "Archie is Branded", he spoke in his normal unaccented voice.

Attended the Cathedral College of the Immaculate Conception in Brooklyn, New York, which was a preparatory school for boys considering the priesthood.

Worked with the National Shakespeare Company and in the New York Shakespeare Festival, appeared in off-Broadway productions and, in one brief brush with Broadway, was a standby in "The Ninety Day Mistress" in 1967.

Has two step-daughters, and one step-granddaughter.

Upon Sierra's death, he was cremated and his ashes were given to his wife.