Robert Emmett O'Connor was an American film actor. He appeared in 204 films between 1919 and 1950. He is probably best known as the warmhearted bootlegger Paddy Ryan in The Public Enemy and as Detective Sergeant Henderson pursuing the Marx Brothers in A Night at the Opera. He also appeared as Jonesy, in Billy Wilder's 1950 film Sunset Boulevard.
He also made a cameo appearance at the very beginning and very end of the MGM cartoon short Who Killed Who?.