Lonny Chapman was an American television actor best known for his numerous guest star appearances on drama series, such as Storefront Lawyers, Quincy, M.E., The A-Team, Murder, She Wrote, Matlock, and NYPD Blue. In the 1954 movie "Young at Heart" with Doris Day and Frank Sinatra, he played Ernie the plumber.
He also appeared as a guest star on the CBS adventure/drama Harbourmaster, starring Barry Sullivan, and on the same network's anthology series The Lloyd Bridges Show. He guest starred too in several episodes of NBC's McCloud, which starred his long-time friend Dennis Weaver, whom Chapman had originally urged to go into show business. He also appeared in three episodes of CBS's Gunsmoke opposite Dennis Weaver. He was cast several times on ABC's The Rifleman, twice on the syndicated adventure series, The Everglades, starring Ron Hayes, and once each on the syndicated crime drama Decoy, starring Beverly Garland, and the short-lived CBS western, Dundee and the Culhane. In 1964 he appeared on Perry Mason as murderer Jack Talley in "The Case of the Tandem Target."
In 1966, Chapman appeared in the episode "Lone Woman" of Barry Sullivan's NBC western series, The Road West.