She ran for the Michigan Supreme Court in 1972 and won the election and took office in 1973. She ran for re-election 1978. She retired in 1982 two years before her second term was up and Governor William Milliken appointed Lieutenant Governor James Brickley to replace her just before he and Brickley left office.[2]
On the Supreme Court, Coleman was elected the first female chief justice. Coleman is in the University of Maryland Hall of Fame and Michigan Women's Hall of Fame.[1]