Judge Arthur J. Gajarsa was born on March 1, 1941 in the town of Norcia, Italy, located in the province of Perugia. He immigrated to the United States in 1949 at the age of 8, and grew up on the south side of Boston.

Judge Gajarsa received his B.S. in electrical engineering from Rensselaer Polytechnic Institute in 1962, his M.A. in economics from Catholic University in 1968 and his J.D. from Georgetown University Law Center in 1967.

After law school, he served as a law clerk to the Honorable Joseph C. McGarraghy of the U.S. District Court for the District of Columbia (1967-68). He then served as an attorney in the Office of General Counsel for Aetna Life and Casualty Company (1968-69); special counsel for the U.S. Department of the Interior, Bureau of Indian Affairs; an associate with the firm of Duncan and Brown (1971-72); a partner in the firm of Gajarsa, Liss and Sterenbuch (1972-78); a partner in the firm of Gajarsa, Liss and Conroy (1978-80); a partner in the firm of Wender, Murase and White (1980-86); and, finally, an officer and partner of Joseph, Gajarsa, McDermott and Reiner, P.C. (1987-97) until his appointment to the federal judiciary.

While in private practice, he specialized in intellectual property and federal laws pertaining to native americans. He represented the Cayuga Nation in its high profile claim for land and monetary compensation from the state of New York in the early 1980s.

President Bill Clinton nominated Judge Gajarsa for the U.S. Court of Appeals for the Federal Circuit on January 7, 1997 to replace Judge Helen Wilson Nies. He was confirmed by voice vote of the United States Senate on July 31, 1997 and took the bench on September 12, 1997. Judge Gajarsa took senior status on the court effective July 31, 2011. He was the first judge of the U.S. Court of Appeals for the Federal Circuit born outside of the United States and its territories.

Judge Gajarsa is a J.D. alumni and received the 125th Anniversary Medal from the Georgetown University Law Center in 1995, as well as the Paul Dean Award in 1999. Additionally, Judge Gajarsa is has served on the Georgetown University Board of Regents (1994-2000) and Georgetown University Board of Directors (2001-unknown). Tangentially, he served on the Board of Governors of the John Carroll Society from 1992-1999. Judge Gajarsa is currently the chairman of the Rensselaer Polytechnic Institute Board of Trustees.