 He clerked in a store, became a surveyor, and later moved to Endion, Minnesota (now Duluth) in 1852.He became a member of the Minnesota Territorial House of Representatives in 1857 and a delegate to the Minnesota State Constitutional Convention in 1857.Kingsbury was elected as a Democrat to the 35th congress and served from March 4, 1857 to May 11, 1858, when a portion of the Territory was admitted as a State into the Union.