Collins was one of eight children in a pious Methodist farm family in Michigan. While still a college student, he determined to become a missionary to China, but there was no Methodist mission work there, so after graduation he taught for two years at Albion College. In 1847 he was called to New York, where he was ordained an elder and commissioned with Dr. and Mrs. Moses C. White, the first Methodist missionaries to China. They sailed on April 15 and arrived in Foochow (Fuzhou), one of the five treaty ports, four months later. To create an opening for the gospel, Collins opened a school for boys in 1847 and another in 1848. He worked with other missionaries on Bible translation and distribution of tracts. In 1850 he was appointed superintendent of the Foochow Mission. Plagued with illness, he returned to the United States in 1851 and died the following year.