Strachan was born in Berkeley, California. He graduated from the University of Southern California with a B.A. in International Relations in 1965. He obtained his J.D. from the University of California, Berkeley Boalt Hall School of Law in 1968. From 1968 until 1970 he worked for the New York City law firm of Mudge, Rose, Guthrie & Alexander, the same firm Nixon worked for before he ran again for the presidency in 1968.
Strachan, who was recruited by Dwight L. Chapin, came to the White House in 1970 and initially worked as a staff assistant to Herbert G. Klein but was assigned to be H.R. Haldeman's liaison to the Committee to Re-elect the President (CRP) when it was formed in March 1971. CRP would become the center of the Watergate scandal. His duties at CRP focused on areas that he had previous experience with; as an advance man during 1970 mid-term election campaigns, he oversaw political operations. He testified as such before the Senate Watergate Committee and stated that John Dean oversaw all political intelligence-gathering, including the Watergate break-in, at CRP.
Strachan was indicted along with other White House staffers on March 1, 1974, but all charges against him were dropped on June 10, 1975.
He moved to Utah in 1975, and served as a clerk for Berman & Giauque in Salt Lake City. In 1977 his license to practice law was restored in Utah, and he was elevated to a lawyer at the firm, until he left for a partnership at Prince, Yeates & Geldzahler. He now is the principal at his own law firm, Strachan Strachan & Simon P.C., in Park City, Utah. His practice is mainly focused on antitrust litigation in the ski industry. He served on the Olympic Organizing Committee for the 2002 Winter Games, and is also general counsel to the United States Ski and Snowboard Association. He is the author of several articles on law.