A South Dakota native, Mr. Parkinson attended the University of South Dakota and then Northern State College, where he obtained a Bachelor of Science degree in 1976. He then worked for four years in Washington, D.C. as an assistant to South Dakota Congressmen Larry Pressler and James Abdnor and as a subcommittee minority staff director. Mr. Parkinson left Capitol Hill to attend Harvard Law School, obtaining his Juris Doctor degree in 1983. While at Harvard, he was an Editor of the Harvard Law Review.

Following law school, Mr. Parkinson was a civil litigator with the law firm of Ropes & Gray in Boston and Washington, D.C. He also served as a Judicial Law Clerk to U.S. District Judge William Young in Boston.

Mr. Parkinson joined the United States Attorney's Office for the District of Columbia, where he served as an Assistant United States Attorney for approximately nine years, from 1986-88 and 1989-95.

In 1988-89, Mr. Parkinson served as General Counsel of the U.S. Small Business Administration, where he managed and directed a legal office of over 200 attorneys.

In 1995, Mr. Parkinson joined the Federal Bureau of Investigation as Deputy General Counsel. In 1997, he was selected to be FBI General Counsel/Assistant Director, where he served for five years, under FBI Directors Louis J. Freeh and Robert S. Mueller. In that position, Mr. Parkinson was responsible for all legal affairs in the FBI and was at the leading edge of a broad range of law enforcement, intelligence, and counterterrorism matters.

In July 2002, Mr. Parkinson joined the U.S. Department of the Interior, where he currently serves as Deputy Assistant Secretary for Law Enforcement and Security.