John Angus Chamberlain was born on April 16, 1927, in Rochester, Ind., the son of a fifth-generation saloonkeeper. He was raised above a meat market until he was 4, when his parents divorced. His mother, a sometime waitress, took him to Chicago, where he was left in the care of his maternal grandmother, Edna Brown Waller, whom he described as a strong, voluble presence in his life.

In his teens, he grew to love classical music but decided he didn’t have enough talent to pursue a music career. Mostly to stay out of trouble, he joined the Navy at 16 in 1943, lying about his age, and served in the Pacific and Mediterranean before returning to Chicago to study hairdressing on the G.I. Bill — an occupation he saw partly as a good way to meet women. Between shifts as a hair and makeup instructor at a modeling school, he tried to teach himself to draw but grew frustrated and enrolled in private art classes. He later entered the School of the Art Institute of Chicago but lasted only a year and a half because of quarrels with instructors he accused of being narrow-minded.

Through a friend, Mr. Chamberlain found Black Mountain College in North Carolina, which he attended in 1955 and 1956. It introduced him to like-minded artists, most of them poets including Robert Creeley, Charles Olson and Robert Duncan. Shortly after leaving the school he met and married Elaine Grulkowski, his second wife, and the couple had three sons. Two, Angus and Duncan, survive him, as does his fourth wife, Ms. Fairweather, and her daughters, Alexandra Fairweather and Phoebe Fairweather. Elaine Chamberlain died in 1973, and a son, Jesse, died in 1999. Two other marriages ended in divorce.

Early on, Mr. Chamberlain was drawn to the totemic welded constructions that David Smith made from old tools and machine parts. But in 1957, he had an epiphany while staying with the painter Larry Rivers in Southampton, N.Y. Using two fenders he pulled from a 1929 Ford rusting on Mr. Rivers’s property, he made a sculpture by running over the pieces repeatedly with a truck to bend them the way he wanted, then he fitted them together almost like puzzle pieces.

The sculpture, “Shortstop,” opened his eyes to the potential of pre-painted junk metal. And work like it, heavily indebted to his Abstract Expressionist mentors, attracted admirers like the influential collector Allan Stone, who described the young Mr. Chamberlain as “a gruff, hairy” character, “more like a north woodsman than a sculptor.” Many critics saw his early work as an affront. One, writing in The New York Times in 1959, described a Chamberlain work as “a construction from the wreckage of a motor car.”