Graduated from Harvard, 1814, S.T.D. (honorary), 1835, honorary Doctor of Laws, 1860. Studied divinity Cambridge (England) University. Honorary Doctor of Laws, Yale, 1853.
Afterward he taught for one year at the Phillips Exeter Academy and then returned to study at the Harvard Divinity School (class of 1817), after which he served for twenty years as the Unitarian minister of Harvard Church in Charlestown, Massachusetts. During this period, he was active in his parochial duties and in advocating the cause of school and college education, lectured extensively and with success, and was a close student of literature and philosophy. In 1838, Walker was appointed Harvard's Alford Professor of Natural Religion, Moral Philosophy, and Civil Polity, which position he held until 1853, when he was elected president of the college.
During his administration, music was added to Harvard's curriculum. He was president at Harvard until his resignation in 1860. He devoted the remainder of his life to scholarly pursuits, and left his library and $15,000 to Harvard, where he received the degree of D.D. in 1835.
At Yale he received the degree of LL.D. in 1860. In 1829 Walker married Catherine Bartlett (1798-1868). They had no children.
Walker also served as a Fellow of Harvard College (1834-1853) and a member of its Board of Overseers (1825-1836, 1864-1874).
Married Catherine Bartlett, December 21, 1829, no children.