He was one of ten children born to Henry Olin (1768–1837), a member of the U.S. House of Representatives from Vermont,[2] and Lois Richardson (d. 1814).

[4] Seeking a better climate for his poor health, Olin traveled to the southern United States, where he found employment as a teacher at Tabernacle Academy in Mount Ariel, in the Abbeville area of South Carolina.

[5] After having a religious awakening at the age of 25, he gave up consideration of the practice of law and became ordained into the Methodist Episcopal Church;[6] Olin was recognized as a deacon by the Milledgeville, Georgia, conference in January 1826.

[6] In 1844, at the general conference of the Methodists, Olin called on his friend, Bishop James Andrew, to resign his office, on the grounds the latter owned slaves.

[4] The Williamsbridge neighborhood of Olinville in the Bronx, New York, began as two towns named for him (founded in 1852).