Harrington graduated from St. Mary's Boys High School in Lynn, and attended Saint Louis University on a basketball scholarship.

He taught government and history and coached basketball at Merrimack College.

[3] He was a member of the Salem City Council during 1957–1959 and was elected to the State Senate in 1958.

[4] He was touted as a primary challenger to governor Mike Dukakis until he retired from the Senate in 1978 amid an investigation into a $2,000 illegal campaign check he allegedly cashed in 1970.

Because of his work at Saint Anselm College, The Kevin B. Harrington Student Ambassador Program is named in his legacy.