It’s Michael Murphy...
It was covered by several artists............
From Wiki:
Cover versions
A cover version by Jeff Stevens and the Bullets peaked at number 53 on the Billboard Hot Country Singles chart in 1987.
“Geronimo’s Cadillac” has also been recorded by Hoyt Axton, Cher, Claire Hamill, Jacques Kloes (nl), Lost Gonzo Band, Manfred Mann’s Earth Band, Dick Gaughan, Mary McCaslin, Chris Leslie and Johnny Rivers.
Native Indian singer Bill Miller performs “Geronimo’s Cadillac” on his 1992 live album Reservation Road.