Christensen played for three different ballclubs during his career: the Chicago White Sox (1999–2001), Los Angeles Dodgers (2001), and New York Mets (2002). He made his Major League Baseball debut on April 6, 1999. Christensen last played in a Major League game on April 7, 2002 and is now retired and working as a real estate developer.
Christensen is a member of The Church of Jesus Christ of Latter-day Saints, and reportedly passed up a million-dollar signing bonus in order to serve a mission in Japan. Christensen was originally drafted by the California Angels and was traded to the White Sox while in Japan as a missionary.