Bachelor of Arts magna cum laude, U. Notre Dame, 1956; Juris Doctor, Georgetown University, 1959.
Born in Omaha, Nebraska, Shanahan received a Bachelor of Arts from the University of Notre Dame in 1956 and an Bachelor of Laws from Georgetown University Law Center in 1959. He was in private practice in Ogallala, Nebraska from 1959 to 1983. Shanahan was a judge on the Nebraska Supreme Court, to which he was appointed March 24, 1983, to fill a vacancy created by the death of Judge Lawrence M. Clinton.
Shanahan served in that capacity until 1993.
On August 6, 1993, Shanahan was nominated by President Bill Clinton to a new seat on the United States District Court for the District of Nebraska created by 104 Statistics 5089. He was confirmed by the United States Senate on November 20, 1993, and received his commission on November 22, 1993.
He assumed senior status on May 5, 2004 and retired on February 1, 2007. He died on December 27, 2011.
M. Jane Estelle Lodge, August 4, 1956. Children: Catherine Shanahan Trofholz, Thomas M. II, Mary Elizabeth, Timothy F.