In 1878, a year after his move to Indianapolis, Taggart married Eva Dora Bryant (1853–1937), whom he met while living in Garrett. Thomas and his wife were the parents of six children, five daughters and one son. Florence Eva (1878–1899) died tragically in a yachting accident in the Gulf of Mexico; Lucy Martha (1880–1960) became an accomplished artist and art educator at the John Herron Art Institute in Indianapolis; Nora (born 1881), a Vassar College graduate, married David L. Chambers, who became president and chairman of the Bobbs-Merrill Company; Irene Mary (born 1883) married a physician from Louisville, Kentucky; Emily Letitia (born 1888) married William R. Sinclair, an executive with Kingan and Company, an Indianapolis-based meatpacker; and Thomas Douglas (born 1886) graduated from Yale University and in 1912 assumed management of the French Lick Springs Hotel. Thomas and Eva Taggart also had nine grandchildren.