Clark was born on Mount Desert Island, Hancock County, Maine. He was a grandson of Davis Wasgatt, a soldier of the American Revolutionary War. Influenced by the family altar, at the age of 16 he joined the first Methodist Class formed by the Rev. David Stimson on Mount Desert Island.

Clark graduated from Kents Hill School in 1833. He then graduated from Wesleyan University of Connecticut in 1836.

After some years of teaching at Amenia Seminary in New York, Clark joined the Traveling Ministry of the New York Annual Conference in 1843. He served as Pastor, Educator and Editor, including time spend as the Editor of the Ladies' Repository, an important M.E. women's magazine. This appointment was spent in Cincinnati.

Clark was elected a Bishop in 1864. In 1866 he was called upon to serve as a mediator to reunite the northern and southern branches of the M.E. Church. He also played an important role in healing the spiritual wounds created by the American Civil War.

He was the first President of the Freedman's Aid Society of the Methodist Episcopal Church. Clark College, founded in 1869, was named in his honor. Clark College became Clark University in 1877.

Bishop Clark became one of the most pouplar and best known Methodist leaders during the post-Civil War years.

He died in Cincinnati, Ohio, May 23, 1871. At the time of his death, he was one of the country's leading religious personalities.

• Elements of Algebra: Embracing Also the Theory and Application of Logarithms. New York: Harper & Brothers, 1846.
• Man All Immortal; or, The Nature and Destination of Man as Taught by Reason and Revelation. Cincinnati: Poe & Hitchcock, 1866.
• Mental Discipline: With Reference to the Acquisition and Communication of Knowledge. New York: Lane & Tippett, 1847.
• Sermons for the College. Akers, 1851.

::Note: Many other works which were edited by Rev. Clark are currently available at Google Books.