Thomas Hastings entered the firm of Herter Brothers at age 17 in order to learn the fundamentals of architecture. Private tutors prepared him for the entrance examination at the Ecole des Beaux-Arts, which he entered in 1880. He remained in Paris some four years, studying under Jules Andr‚. When he returned to New York, he accepted employment with the firm of McKim, Mead, and White. The following year, he and John Carrére, another McKim, Mead, and White employee, formed their own partnership which lasted until Carrére's death in 1911.
Although Carrére and Hastings became known for their French Renaissance-inspired buildings, their first major commission was Spanish in character, the Ponce de Leon Hotel in St. Augustine, FL (of which the Academy possesses a Hastings drawing). Major buildings in New York followed, such as the Henry Frick House (1895) and the New York Public Library (1897-1911). Carrére and Hastings's designs for a new National Academy building on Cathedral Parkway were chosen from among six competitors, but the plans were never realized. Hastings was elected an Associate of the Academy in 1906 and a full Academician in 1909. He was active in many professional organizations and served as a professor in Columbia University's School of Architecture.
