After graduating from high school, Jack Elrod joined the Navy in 1942. During the next three and a half years, he participated in various engagements in the Pacific and in the occupation of Japan. He then studied advertising design and lay out in Nashville and graduated from the Atlanta Art Institute in 1949. In 1950 he joined 'Mark Trail' creator Ed Dodd and another artist, Tom Hill, in an art studio in Atlanta.
Hill and Elrod both assisted Dodd on the wildlife series 'Mark Trail' for several years. In 1978, Elrod took over the series completely, when Dodd retired and Hill, who did the Sunday pages, died. Elrod added several new characters to the series and even let Mark Trail get married at one point. He was assisted by James Allen from 2010. Elrod and Allen became primary artist of the strip in April 2014. Besides 'Mark Trail', Elrod succeeded Cal Alley on 'The Ryatts' from 1965 until 1994.