When he was five years old, his father, after teaching in West Virginia, was offered a professorship in Eugene, Oregon and the family relocated.

[4][5] He was selected in the 1974 Major League Baseball draft, but he elected to play football at Brigham Young University (BYU) in Provo, Utah.

[6][2] At BYU, Christensen was a four-year starter (1974–1977) for the Cougars at fullback, led the team for three consecutive seasons in receiving and was an All-Western Athletic Conference selection as a senior in 1977.

Christensen was claimed off waivers by the New York Giants but only played in one game and lasted two weeks with the team, before being released to make room for wide receiver Dwight Scales.

[7] After being unclaimed, he was signed by the Oakland Raiders in 1979 and became a key player on special teams, which included the role of long snapper.

Being the son of a college professor, he was scholarly and enjoyed the mastery of words, he also quoted famous authors and volunteered on different occasions poems, some of which were written by him.

He finally agreed to play the tight end position and after three seasons of unspectacular statistics (including the Raiders' Super Bowl winning campaign in 1980, in which his only reception of the entire year was a 1-yard touchdown catch in the opening round of the playoffs), Christensen broke out in 1982, catching 42 passes for 510 yards and four touchdowns during the strike-shortened season, helping the Raiders tie the Washington Redskins for the best record in the NFL.

The next year, Christensen caught 92 passes for a career-high 1,247 yards and 12 touchdowns and earned the first of his five trips to the Pro Bowl for his efforts.

"[10] Christensen did color commentary for ESPN's college football coverage before moving to MountainWest Sports Network.

Christensen died at age 57 on November 13, 2013, from complications during liver transplant surgery at Intermountain Medical Center in Murray, Utah, near his home in Alpine.