A native of The Bronx borough of New York City, and a graduate of the University of Michigan, he appeared in 151 films or television programs. Maxwell began his acting career on the Broadway stage, appearing in such notable plays as Death of a Salesman, South Pacific, Alfred Hitchcock Presents, The Fugitive, Whirlybirds, Black Saddle, The Man and the Challenge, The Deputy, Cain's Hundred, Follow the Sun, Hong Kong, The Asphalt Jungle, , and Mr. Novak. He was cast three times each on Robert Montgomery Presents, Cannon, and Emergency! and four times each on Rawhide, Quincy, M.E., and The F.B.I. In 1960, Maxwell was cast in CBS's science fiction series, The Twilight Zone as Marty Fisher in the episode "A World of Difference". That same year, he appeared as Hackett in the episode "Millionaire Jessica March" of the CBSfantasy drama, The Millionaire. In 1960 he made two guest appearances on Perry Mason: as Harry Wilson in "The Case of the Wayward Wife," and defendant Joe Dixon in "The Case of the Red Riding Boots." He made a third appearance in 1961 as Dr. Mooney in "The Case of the Injured Innocent." In the 1962–1963 television season, he was a co-star of the ABCsitcom, Our Man Higgins, starring Stanley Holloway in the title role and with Audrey Totter and Ricky Kelman. Maxwell played the father, Duncan MacRoberts, in all thirty-four episodes of the series. He also appeared as a regular on the TV series "Felony Squad" with Howard Duff from 1966-68 and "The Second Hundred Years" with Monte Markham from 1967-68. From 1973 to 1975, he appeared in five episodes of CBS's Barnaby Jones, with Buddy Ebsen. In 1977, he appeared an in episode of ABC's The Feather and Father Gang. In 1984, he appeared in a two-part episode of ABC's The Love Boat, in which he was cast as Colonel Charles Holmsey. His last regular acting role was as Dan Rooney, the lovable aging hospital administrator on General Hospital which he appeared on from 1978-1988. Over the years, the character had a hand in practically every storyline and was a major participant in the now famous "Ice Princess" storyline which dominated the daytime ratings in 1981.