Born at Dayton, Pennsylvania. Attended Beaver (PA) College. Moved to Buffalo, New York.

Elder was a government telegrapher assigned to the home of President William McKinley who was dying after being shot in 1901. He served as a sergeant in the New York State Militia during World War I. He married Sophie Faskett Howley in November 1908. Married to Ruth Marguerite Compton in 1923.

He began collecting coins at age 13 after collecting Indian arrow heads, fossils and tobacco tin tags. Elder joined the ANA in 1899 and the ANS January 18, 1904. He became a professional numismatist and conducted his first auction September 30, 1905. He conducted 294 auction sales with 422,336 lots from 1903 to 1940. It was claimed that he could catalog a thousand lot auction in 24 hours.

He was one of the founders of the New York Numismatic Club in 1907. He contributed several articles to The Numismatist. Published the Elder Rare Coin Book in 1913 and The New Rare Coin Book in 1934. He published The Elder Monthly March 1906 to 1907, and The Elder Magazine 1910 to 1911.

When Farran Zerbe took over publication of The Numismatist, Elder published The Numismatic Philistine in response. Elder issued satirical tokens attacking Zerbe.

He collected medals of Benjamin Franklin. His collection of 126 pieces was sold to A. S. W. Rosenbach in 1929.

He died at Travelers Rest, South Carolina. In 2013 he was inducted into the PCGS CoinFacts Coin Dealer Hall of Fame.

Elder produced a number of medals beginning in 1902. He also produced store cards. DeLorey identified 104 tokens issued by Elder. An article on these medals appeared in The Numismatist in June and July 1980.

(See "Thomas L. Elder, A Catalogue of his Tokens and Medals" by Thomas DeLorey) bio: Adams II (photo) obit: NUM 61 Jul 1948 page 469; ANAHist 710 photo: NUM 16 April 1903 page 123