Reggie Bush took the unprecedented step of giving back his Heisman Trophy yesterday, saying the scandal over improper benefits while he was a star running back at Southern California should not stain “the dignity of this award.’’

The New Orleans Saints star won the Heisman — symbol of the best player in college football — in 2005.

Returning the trophy has no practical effect on Bush since he’s already in the pros and a member of a Super Bowl championship team. However, it is the first time in the award’s 75-year history that a player has forfeited it.

USC was hit with heavy sanctions by the NCAA this summer after it determined Bush and his family had received hundreds of thousands of dollars in gifts from two fledgling California-based marketing agents. The NCAA ruled that Bush was ineligible for the 2005 season, which opened the possibility that the Heisman Trophy Trust would take back the award.

One of the few guidelines given to Heisman Trophy voters is that a player must be in compliance with NCAA rules to be eligible for the award.

“The persistent media speculation regarding allegations dating back to my years at USC has been both painful and distracting,’’ Bush said in a statement. “In no way should the storm around these allegations reflect in any way on the dignity of this award, nor on any other institutions or individuals.

“For the rest of my days, I will continue to strive to demonstrate through my actions and words that I was deserving of the confidence placed in me by the Heisman Trophy Trust.’’

Shortly after USC was sanctioned, the eight-member trust, based in New York, said it was considering what to do about Bush, who won in a landslide vote over Texas quarterback Vince Young.

The trust met yesterday; it had no comment. Whether the 2005 Heisman will be vacated or given to Young remains to be seen.

“Reg will continue to be the 2005 Award recipient and I will continue to be honored to have been in the 2005 Heisman campaign with such a talented athlete,’’ Young said via Twitter.

Allegations of improper benefits to Bush and his family led the NCAA to come down hard on USC. The penalties levied included the loss of 30 football scholarships over three years and vacating 14 victories in which Bush played in 2004 and 2005.