James Thompson McCleary was born in Ingersoll, Ontario, Canada, on February 5, 1853. He came to the United States at the age of twenty, and married Mary Edith Taylor in 1874. They had one son, Leslie Taylor.

In 1881, McCleary became State institute conductor in Minnesota, and professor of history and civics in the State Normal School at Mankato. He published Studies in Civics in 1888, and A Manual of Civics in 1894. Both became standard textbooks in the field. In 1883 he was elected secretary of the Minnesota Education Association, and in 1891 became its president. He was elected to the U.S. Congress from the Second District of Minnesota in 1892, and served there until 1907. President Theodore Roosevelt appointed McCleary Second Assistant Postmaster General. He served in that position until 1908. McCleary died in LaCrosse, Wisconsin December 17, 1924.