Born in Los Angeles, California, Stearns received a Bachelor of Arts degree from Stanford University in 1968, a Master of Letters degree (Political Philosophy) from Balliol College, Oxford, as a Rhodes Scholar, in 1971, and a Juris Doctor from Harvard Law School in 1976.

He worked in the Norfolk County (Massachusetts) District Attorney's office from 1976 to 1982.

He was an Assistant United States Attorney of the District of Massachusetts from 1982 to 1990.

On October 27, 1993, Stearns was nominated by President Bill Clinton to a seat on the United States District Court for the District of Massachusetts vacated by John J. McNaught.

Clinton had originally wanted to appoint Stearns Director of the Federal Bureau of Investigation.