He is most familiar today as Uncle Joe Carson from the Petticoat Junction,[1] Green Acres, and The Beverly Hillbillies television sitcoms of the 1960s.

[5] According to authors Arden and Joan Christen, Edgar's father believed "to choose a career in the theater was to settle for a life of mediocrity and uncertainty".

[5] Nevertheless, Edgar took courses in theater at the University of Oregon as a pre-med student, and was part of a Portland acting troupe in graduate school.

[10] Buchanan appeared in more than 100 films,[11] including Texas (1941), in which he played a dentist and appeared with William Holden and Glenn Ford and later in Penny Serenade (1941) with Irene Dunne and Cary Grant, Tombstone, the Town Too Tough to Die (1942), The Talk of the Town (1942) with Ronald Colman, Cary Grant and Jean Arthur, The Man from Colorado (1948), Cheaper by the Dozen (1950), Shane (1953), She Couldn't Say No (1954), Ride the High Country (1962) with Randolph Scott and Joel McCrea, McLintock!

[13] In addition to several other widely varying roles on the series (running the gamut from sympathetic parts to vicious villains), he portrayed Jed Christianson in the episode "Duel at Sundown" on Maverick with James Garner and Clint Eastwood.

He was on Leave It to Beaver (as both "Uncle Billy" and "Captain Jack"), The Twilight Zone, Riverboat (as Wingate Pardee in the 1960 episode, "Duel on the River"), Gunsmoke (in 1962 as the title character “Old Dan” - S7E18), Route 66, Bringing Up Buddy, Bus Stop, and The Lloyd Bridges Show.

[12] Buchanan's roles as a regular cast member in television programs included Red Connors in the syndicated Western Hopalong Cassidy,[14] and J.J. Jackson in the CBS crime drama Cade's County.