Brown University; Harvard Law School.
Walker earned degrees from Phillips Exeter Academy, Brown University, Harvard College, and Harvard Law School. He was admitted to the Suffolk County bar in 1889. He also served on the Town Committee and was a Republican State Committeeman.
In 1904 Walker was elected to the Massachusetts House of Representatives.
He served as chairman of the House Rules, Ways, and Means Committee, the special State Accounts Committee, and the Railroads Committee. In 1909 he was elected Speaker of the House.
Walker was a candidate for Governor of Massachusetts in 1911, but lost the Republican nomination to Lieutenant Governor Louis A. Frothingham. He ran again in 1912, but lost in the general election to Governor Eugene Foss.
He finished in third place with 7.02% of the vote.
Walker died on November 26, 1941 at the Phillips House of the Massachusetts General Hospital.
Walker was a member of the Brookline School Committee from 1897 to 1903. He ran a third time in 1914 as a member of the Progressive Party.