Born in Jersey City, New Jersey, Russoniello graduated from Saint Peter's Preparatory School in Jersey City, NJ, in 1959. He received a B.S.S. degree from Fairfield University in 1963 and a J.D. degree from New York University Law School in 1966. After graduating from the NYU School of Law Russoniello was appointed a Special Agent with the Federal Bureau of Investigation, and later served as an Assistant District Attorney for the City and County of San Francisco before joining Cooley Godward Kronish LLP in 1975.

From January 1982 to March 1990, Russoniello served his first term as the U.S. Attorney for the Northern District of California. He personally prosecuted Larry Layton of the Peoples Temple for his part in the murder of Congressman Leo Ryan in Jonestown, Guyana, and tried several other high profile Criminal and civil cases.

Before returning to the U.S. Attorney's Office, Russoniello was Senior Counsel and resident in the San Francisco office of Cooley Godward Kronish LLP where he was a member of the Litigation department and the practice group for Business Crimes & Regulatory Defense. Russoniello also served as Dean of the San Francisco Law School for five and a half years until his resignation in July 2007.

In 2008, Russoniello was nominated again to serve as the U.S. Attorney for the Northern District of California (which encompasses the 15 counties from the Oregon-California border to Monterey, including the San Francisco Bay Area). Upon taking office, Russoniello indicated that his priorities during his second term would include national security, helping to get guns off the street and prosecuting Internet child pornography distribution. He is also overseeing his office's prosecution of Barry Bonds, former San Francisco Giants outfielder and all-time Major League Baseball home run king, on perjury charges, as well as Ed Jew, former Member of the San Francisco Board of Supervisors, on extortion and bribery charges. Russoniello was succeeded in August 2010 by Melinda Haag.