Riley gave up the radio show in the mid-1960s and moved to Los Angeles, where his Cleveland friend Tim Conway helped him obtain work writing comedy sketches, which later led to acting opportunities.

[9] He was also a favorite of Mel Brooks, appearing in several of his films: High Anxiety (1977), History of the World: Part I (1981), To Be or Not to Be (1983), and in a cameo in Spaceballs (1987).

[9][4] Riley often provided voiceovers for television and radio commercials, most notably in spots for Country Crock margarine.

[10][11] In the 1990s and early 2000s, Riley was known for voicing Stu Pickles (father of the main protagonist Tommy) in the animated series Rugrats.

[12] He made a cameo appearance on the November 23, 2013, episode of Saturday Night Live, as a subway passenger during the sketch "Matchbox 3".