Question: what actor has been on tv the longest?
Answer: Peter Sallis – Cleggy (Last of the Summer Wine): 37 years.
Peter Falk – Columbo: 35 years. ... 
Warren Mitchell – Alf Garnett (Till Death Us Do Part/In Sickness and In Health): 32 years. ... 
John Challis – Boycie (Only Fools and Horses/The Green Green Grass): 30 years. ...