Titus George LeClair was born in Superior, Wisconsin, August 26, 1899, the son of James Van Renselaer and Jessie Ethel (Fish) LeClair. His family moved to Lewiston, Idaho when he was five years old. He attended schools in Lewiston and was valedictorian of his 1917 graduating class.

He then attended the University of Idaho where he graduated with the degree B.S.E.E. in 1921. While at the university he was president of the Associated Engineers and chairman of the student A.I.E.E. group. In addition he was a member of the glee club and the university quartet. He entered the Student Officers Training Corps while continuing as a full-time student, but was released in December 1918 following the Armistice. He was awarded an honorary D.Sc by the university in 1951.

Following graduation from the university he began work as a testing engineer for the General Electric Company in Schnectady, New York.

In 1923 he moved to Chicago where he began a long association with the Commonwealth Edison Company, which was one of the first industrial companies permitted to have access to atomic secrets for power plant studies. He was also involved with the Nuclear Power Group, a corporation formed to cooperate in the building of the 180,000 kw Dresden Nuclear Power Station owned by Commonwealth Edison.

In 1960 he left Chicago for San Diego, California where he was associated with General Dynamics Corporation, General Atomic Division, as manager of nuclear power applications.

LeClair was recognized as a leader in the development of nuclear power for central station generation of electricity, and served in advisory capacities on the Atomic Energy Commission and the Joint Congressional Committee on Atomic Energy.

He was the inventor of several devices used in the electrical industry including relay schemes, switching schemes, automatic printing meters, and special conductors. He was also the author of many papers read before engineering societies and published in the technical press.

He was president of the American Institute of Engineers in 1950-1951, and was a member of the American Society of Engineering Education, the Professional Engineers' Examining Committee of the State of Illinois, the Illinois Society of Professional Engineers, the National Society of Professional Engineers, the Western Society of Engineers, Sigma Nu, Eta Kappa Nu, and Tau Beta Pi.

On May 26, 1922 he married Alice Bessee, whose adaptation of the melody of "Garden of Paradise" became the music for the Idaho State Song: "Here We Have Idaho." They had three sons before her sudden death in September 1928. On March 15, 1930 he married Amelie McGuire, with whom he had a daughter.

He continued to be active in his profession until his death. On March 26, 1968, while attending a major Southwest Electric Exchange conference in Boca Raton, Florida, he went swimming in the Atlantic Ocean during a break in the conference activities, and died while swimming.