Longest running 'non-animated' character on prime time television (US)

Longest running 'non-animated' character on prime time television (US)
Who
Marshall Matt Dillon, Dr Frasier Crane
Where
()
When
2004
Two characters played by the same actors dominated the prime time slots on American TV for 20 years each. The first was Marshall Matt Dillon, portrayed by James Arness (USA) on the western Gunsmoke (CBS, USA, 1955-1975); the second was Dr Frasier Crane (aka Kelsey Grammer, USA) in Cheers (NBC, USA, 1982-1993; appeared 1984-993), Wings (NBC, USA, 1990-1997; a guest appearance in 1992) and Frasier (NBC, USA, 1993-2004).