Thomas Taggart was born on November 17, 1856, to Thomas and Martha Kingsbury Taggart in Emyvale, County Monaghan, Ireland, and immigrated with his family to the United States in 1861 at the age of five. The Taggarts settled in Xenia, Ohio, where Thomas senior worked at a local railroad depot. Young Taggart left high school early to work full-time at the depot's hotel and restaurant. In 1875, when young Thomas was 18, his employer, the N. and G. Ohmer Company, sent him to Garrett, Indiana, to work in the restaurant at DeKalb House, a depot hotel. Thomas remained at Garrett until 1877, when he was transferred to Indianapolis, Indiana, to work as a clerk for the Ohmer company's dining hall/restaurant at the city's Union Depot. Known as a hard worker, Taggart became the depot restaurant's manager and eventually its sole owner in the new Union Station.