McLaughlin emigrated to the United States at the age of 21, living briefly in St. Paul, Minnesota, where he married a Mdewakanton woman of mixed-blood descent. He soon became a citizen. While working as a blacksmith at Fort Totten, he studied to become a U.S. Indian agent, and was selected to supervise the Devils Lake Agency in 1876. He was promoted and transferred in 1881 to the larger Standing Rock Sioux Agency in the Dakotas, working there for many years, in an era of short-term political appointments. In 1895 he was promoted to a position as Inspector of the Bureau of Indian Affairs and Department of Interior, working until his death in 1923 in Washington, D.C.