Charles Fahy was born on August 17, 1892, in Rome, Georgia. He was the son of Thomas and Sarah (Jonas) Fahy. Charles attended the University of Notre Dame and upon earning his bachelor's degree in 1911 proceeded directly to Georgetown University Law School. There he received his law degree in 1914 and was admitted to the D.C. bar in the same year. He served the United States in World War I as a naval aviator attached to the British and American forces. Fahy was awarded the Navy Cross. After the war he returned to Washington D.C. and practiced law until 1924. He moved his family and practice to Santa Fe, New Mexico, where he resided until 1933. While in Sante Fe, Fahy served as the city attorney in 1932.
In 1933, Fahy returned to Washington when he was appointed first assistant solicitor to the Department of the Interior. That same year he was appointed as a member of the Petroleum Administrative Board, and then served as its president from 1934-1935. As general counsel of the National Labor Relations Board from 1935-1940, Fahy began his career in Supreme Court litigation on behalf of labor rights. Upon the enactment of the Wagner Act in 1935, Fahy, on behalf of the NLRB, often appeared in front of both Houses of Congress to offer testimony and litigated cases in the Supreme Court brought against the government. By the time he was appointed assistant solicitor general in 1940, Fahy had already appeared eighteen times in front of the Supreme Court, where his arguments were wholly sustained sixteen times and partially upheld twice.
Fahy was appointed solicitor general by President Roosevelt on November 1, 1941. While SG, Fahy continued to advocate for worker's labor rights, and was involved in cases regarding the constitutionality of wiretapping and the citizenship of American Communists. He served as SG until 1945, after having argued more than 70 cases in front of the Supreme Court, before being called upon by General Eisenhower to serve as director of the legal division of the U.S. Group Control Council in Germany in the aftermath of World War II. After returning from his tour of duty in Germany, Fahy was a legal advisor in the Department of State. He was also a member of the U.S. Legal Committee of the General Assembly of the United Nations, held in New York City in 1946.
Fahy returned to private practice in 1947, but was again called to serve the federal government as chairman of the President's Committee on Equality of Treatment and Opportunities in Armed Forces, from 1948-1950. In 1949, he was appointed a judge on the U.S. Court of Appeals for the D.C. Circuit, and was made a senior judge in 1967 - a position which he held until his death in 1979.
Fahy was the recipient of a number of awards, including a medal for military merit (1946), the Robert S. Abbott Memorial Award (1951), John Carroll Award from the Georgetown University Member Alumni (1953), and the D.C. Distinguished Service Award (1969). Charles Fahy passed away on September 17, 1979, at the age of 87 in Washington, D.C. He was survived by his wife Mary Agnus Lane, and children Charles (Dom Thomas Fahy O.S.B.), Anne Marie (Sheehan), Sarah Agnes (Sister Sarah Fahy S.N.D.), and Mary Agnus (Johnson).