The young man took a course in architectural design at Schofield’s College.
Between 1846 and 48 he worked as a builder’s assistant. During the Civil War he served with the Union Army, and after returning home continued a member of the Rhode Island State Militia for twenty years.
Beginning architectural work in Providence in the late 'sixties Mr. Walker designed the Union Congregational Church (1872), the City High School, and Bell Street Chapel. Then in 1876 he formed a partnership with Thomas T. Gould (Walker & Gould) and among their most important works were the Vaughan Office Building, Daniels Building, Aldrich Building, and the Library at Brown University, the latter the firm's most successful building. After 1881 Mr. Walker practiced jointly with his son, William Howard Walker, and in the latter years of the century planned a number of churches and schools, also State Armories and City Halls in various cities in the state.