In 1976, on the recommendation of his peers at the Bar Association, Governor Michael S. Dukakis appointed Justice O'Connor to the Massachusetts Superior Court, where he served with distinction for 5 years.

[10] Later that month, the Massachusetts Governor's Council made the unusual move of suspending the customary one-week waiting period, and voting unanimously in favor of O'Connor's confirmation the same day as his hearing.

[12] Justice O'Connor was widely recognized in the legal community for the respectful tone he set in the courtroom, his honesty, his integrity, and the courtesy he extended to all parties and counsel who appeared before him.

In one such dissent, O'Connor argued that the Court majority's decision to create 'buffer zones' between protestors and abortion clinics would "impermissibly chill" people's right to protest.

[16] Similarly, in 1993 O'Connor acted for the court when he refused to sign an injunction which prohibited queer people from marching in South Boston's St. Patrick's Day Parade.

"[18] In recognition of his year's of service to the Supreme Judicial Court Substance Abuse Project Task Force, O'Connor was named honorary chairman upon his retirement.

Justice O'Connor served our highest court with honor and distinction for many years and was widely respected and admired for his intellect, his integrity and humanity, and his commitment to the legal community and beyond.