He died of pneumonia at a hospital in Los Angeles and is survived by his wife Ginger Lawrence, two children and two grandchildren, according to Paul Doherty at Cunningham Escott Slevin & Doherty, reported Variety.
Riley gained recognition for his role as the selfish and neurotic patient Elliot Carlin, who is credited in 49 episodes of "The Bob Newhart Show."
He was also a voice actor for the iconic Nickelodeon character in "Rugrats" for over a decade starting in 1991. He voiced 143 episodes of the original series through 2005, and 18 episodes of the "Rugrats" spin-off "All Grown Up" until 2007.
Riley's career spanned close to 50 years and he has amassed 157 credits over that duration.
He was also a regular in "Diff'rent Strokes," "Night Court" and "Son of the Beach."
In addition to his career on television, Riley was a part of several Mel Brooks films including "Silent Movie," "High Anxiety," "History of the World: Part I" and "Spaceballs.