Thomas Cain was born in Columbia, South Carolina, the son of Elias Horlbeck and Harriet Lowndes Cain.
At the age of 12, he was employed as an office boy in the law office of Washington Clark. At the age of 16, he was employed with the firm of Thomas and Lumpkin as an office boy and clerk associate.
He was educated in the Columbia public schools, graduated from the University of South Carolina, where he was a member of ODK, and graduated from the University of South Carolina Law School in 1924. He also did graduate work at Columbia University. He returned to Columbia and became a partner in the firm of Thomas, Lumpkin and Cain. He specialized in life insurance law. He prepared and published a complete digest of the South Carolina statutes and case laws on insurance. At the time of his death, he was a senior partner in the firm of Thomas, Cain and Nettles.
He was an insurance counsel without peer. He served as general counsel and Director of the Standard Building and Loan, as a member of the American Judicature Society, the American Law Institute, and was a member of the American Bar Association House of Delegates.
He was survived by his beloved wife, Julia Long Cain, sisters, Anne Luttrel, Margaret Harvin, Charlotte Cain and his brother and law partner, William Cain.
To Cain, adversity was no barrier. He was an exemplary, industrious and conscientious trial attorney, a loving, attentive son, and a devoted, affectionate husband.