Gair was admitted to the bar of New York in 1919. He was a lecturer on Medical-Legal Jurisprudence, at Columbia University Law School, at New York University Law School and Vanderbilt University. He was a fellow of the American College of Trial Lawyers and a member of the International Academy of Trial Lawyers where he served as Dean from 1956 to 1957 and as Director from 1954 to 1955. He was also a member of the Law-Science Academy of America where he served as President from 1953 to 1955.