Ohlson was born on November 18, 1936, in Cherokee, Iowa and attended Bethel College before serving in the United States Marine Corps. After completing his military service, he attended the University of Minnesota, where he was awarded a degree in studio art in 1961. He moved to New York City, where he studied at Hunter College under abstract sculptor Tony Smith, but dropped out when he could no longer afford tuition. He worked as an assistant to Smith and started teaching at Hunter College in 1964.
Ohlson died at age 73 on June 29, 2010, after a fall in front of his Manhattan apartment. He was survived by his second wife, Michele Toohey. He was divorced from his first wife, painter Jane Kaufman.Wikipedia