Parker was born in Charlestown (now part of Boston), Suffolk County, Massachusetts on March 2, 1856.

[2] His maternal grandparents were Anna (née Morse) Felton and Cornelius Conway Felton Sr.

He was a lawyer and served as Attorney General of Massachusetts from 1902 to 1906.

[6] Parker was married to Mary Carney Vose, a daughter of Caroline Cushing (née Forbes) Vose and Lt. Josiah Hayden Vose Jr., who was killed at the Battle of Port Hudson in the U.S. Civil War.

Together, they were the parents of:[7] Parker died on February 11, 1939, at his home in Lancaster, Massachusetts.