Christensen's son, Toby Christensen, said his father died Wednesday morning at Intermountain Medical Center near his home in Alpine, Utah.
"I've been receiving hundreds of texts, Facebook postings and emails - from everybody with a story about my dad," Toby Christensen said.
After a stellar career at running back for BYU from 1974-77, Christensen was a second-round pick for the Dallas Cowboys in the 1978 NFL draft.
He was waived by the Cowboys after breaking his foot in training camp but landed the next year with the Raiders, where he played for 10 seasons at tight end and won Super Bowls in 1981 and 1984.
In 1983, he had 92 catches, setting the NFL record at the time for tight ends. He finished the season with 1,247 yards receiving and 12 touchdowns.
He broke his own record three seasons later with 95 catches. He finished his pro career with 467 catches for 5,872 yards and 41 touchdowns. He surpassed 1,000 yards receiving in three different seasons.
Christensen, at 6-foot-3 and 230 pounds, never fit the Raiders' untamed mold. He was a thoughtful son of a professor, and even read his own poetry at a Super Bowl press conference. He later self-published three books of poetry.
Christensen played on four Western Conference Championship teams for BYU, catching 152 passes for 1,568 yards and 15 touchdowns. He was inducted into the school's Hall of Fame in 1992.
"He had great skill," BYU football Hall of Fame coach LaVell Edwards told the Daily Herald of Provo, Utah. "He ran the ball well and he caught the ball extremely well. He had excellent ability in all areas and those are the things that stand out."
Christensen was a color commentator for the NFL on NBC from 1990-94, and did color commentary for ESPN and the now-defunct MountainWest Sports Network before handling Navy games for CBS Sports Network in the 2012 season.
Christensen was a devout Mormon who didn't drink, and his family believes his liver problems started 25 years ago after a "botched" gall bladder operation, his son told The Associated Press.
A native of Pennsylvania, Christensen's family moved to Eugene, Ore., when he was a child and he became a standout at Sheldon High School. He was later inducted into the Oregon Sports Hall of Fame.
Christensen is survived by his wife and four sons. The family was making plans for a funeral as early as Saturday at a local Mormon church ward house in Alpine.
AP Sports Writer Anne M. Peterson in Oregon contributed to this report.