In his first start in the fifth game against Washington State University, he set a school single-game record with 12 receptions.
He was also the MVP of the 1991 Hula Bowl, and finished his NCAA football career with 103 receptions for 1,547 yards and 16 touchdowns.
In the 1991 NFL draft, the Dallas Cowboys sought a receiving partner for starter Michael Irvin and selected Harper in the first round (12th overall).
He probably had the signature play of his career during the NFC Championship against the San Francisco 49ers, catching a slant route for 70 yards, setting up the Cowboys on the 10-yard line and sealing the win.
He also caught a 45-yard touchdown from quarterback Troy Aikman during the 52–17 victory over the Buffalo Bills in Super Bowl XXVII, after which he dunked the ball over the goal post crossbar.
On March 8, 1995, Harper signed a lucrative free agent contract with the Tampa Bay Buccaneers based on his big play ability and championship experience.
[3] Though he had a career-high 46 receptions for 633 yards and 2 touchdowns in his first season in Tampa, he was not able to live up to his free agent billing.
Harper was replaced with Robb Thomas in the second half of the sixth game against the Minnesota Vikings and would lose his job as the starter at wide receiver.
On June 11, 1997, the Washington Redskins signed him, gambling that he could flourish again after being reunited with head coach Norv Turner, who had been his offensive coordinator in Dallas.
[11] On October 14, 1999, he was signed by the Dallas Cowboys, to provide depth after Michael Irvin suffered a career-ending neck injury in the fourth game against the Philadelphia Eagles.