Harry Morgan, the prolific character actor best known for playing the acerbic but kindly Colonel Potter in the long-running television series “M*A*S*H,” died Wednesday morning at his home in Los Angeles. He was 96. His son Charles confirmed his death. In more than 100 movies, Mr. Morgan played Western bad guys, characters with names like Rocky and Shorty, loyal sidekicks, judges, sheriffs, soldiers, thugs and police chiefs. On television, he played Officer Bill Gannon with a phlegmatic but light touch to Jack Webb’s always-by-the-book Sgt. Joe Friday in the updated “Dragnet,” from 1967 to 1970. He starred as Pete Porter,...