[1][2][3][4] Delahanty was a graduate of Saint Michael's College in Vermont in 1967 and the University of Maine School of Law in 1970.

[6][9] Delahanty was nominated by U.S. President Barack Obama on March 10, 2010,[10] appointed on June 23, 2010,[4] and was sworn into office on July 1, 2010.

Delahanty was also a member of both the Medical Marijuana Enforcement Working Group and the Northern Border Initiative Subcommittee.

[11][12][13] Along with fellow former U.S. Attorney Michael W. Cotter, he released his resignation letter to the public after the Justice Department refused to do so citing an exemption to the Freedom of Information Act.

His maternal grandfather, John David Clifford, Jr., was a judge and also previously held the United States Attorney position.