He served in the infantry in Europe in World War II and was awarded the Purple Heart and battle stars.

Champlin was a writer and correspondent for Life and Time magazine for seventeen years, and was a member of the Overseas Press Club.

He co-founded the Los Angeles Film Critics Association, and was a board member of the American Cinematheque.

That same year, he hosted a live music series, Homewood, for KCET, the Los Angeles PBS station.

[4][5] In his later years, since the late 1990s, Champlin had macular degeneration, and in 2001 wrote My Friend, You Are Legally Blind, a memoir about his struggle with the disease.