In two separate court cases, Sharper pleaded guilty to sexual assault in Arizona and no contest in California to raping two women he knocked out with a potent sedative mixed with booze.
Sharper, 39, wearing a striped, light blue suit, said it was in his best interest to enter the pleas.
The pleas came as Los Angeles prosecutors were prepared to present evidence of Sharper's fall from grace as a former all-pro safety who won a Super Bowl with the New Orleans Saints. His clean-cut reputation took a hit when women began telling police in several cities similar stories of blacking out while drinking with him and waking up groggy to find they had been sexually abused.
Defence lawyers had previously said the sexual intercourse was consensual. One lawyer had said Sharper didn't mix the sleepy shots of alcohol.
But Sharper wielded no defence in court Monday.
By not contesting the California charges, he admitted he raped two women he drugged after meeting them at Bootsy Bellows, a West Hollywood bar. The pleas have the same effect as a conviction.
Both encounters were eerily similar.
In October 2013, Sharper invited a woman and her friend to go to a party but stopped on the way to get something at his Century City hotel and invited them upstairs.
He insisted they drink a shot and they blacked out. One woman awoke with Sharper on top of her having sex.
The women were not in court, but prosecutors said they had agreed to the plea.
Under the unusual deal negotiated by Sharper's lawyers and state and federal prosecutors, Sharper will serve sentences concurrently in federal prison, though the full term has not yet been announced.
He was sentenced to nine years in the Arizona case and will face 20 years in the California case when sentenced July 15. However, because the crimes in California only require serving half the term and he gets credit for 13 months spent in jail, he'll serve about nine more years, lawyers said.
The sentence is no slap on the wrist, but it spares Sharper a potentially longer term if sentences involving at least nine alleged victims were added together and he also avoids notoriously rough state prisons, said Jeffery Rubenstein, a former Los Angeles prosecutor.
"This could have gotten really ugly and very likely this guy would have never seen the light of day," said Rubenstein, who didn't work on the case.
From the prosecution standpoint, victims were saved from reliving the event through testimony and having their credibility questioned by a seasoned team of defence lawyers, Rubenstein said.
Hearings will follow in Las Vegas on Tuesday and in New Orleans in the next month. In each state, he's accused of drugging and sexually assaulting women when they were unconscious or otherwise unable to resist or consent.
Sharper's worked as an NFL network analyst after retiring in 2011 from his 14-year NFL career. His arrest reverberated as the league dealt with off-field problems with players accused of crimes ranging from spousal abuse to murder. He was working
Sharper appeared in a Phoenix courtroom by video-conferencing from LA and admitted he sexually assaulted one woman and tried to attack another in suburban Phoenix in 2013.
Prosecutor Yigael Cohen said one victim didn't have the ability to resist and suffered emotional harm.
A search of the Tempe apartment turned up a shot glass with a residue of the sedative zolpidem, sold under the brand name Ambien.
In the California case, he pleaded no contest to four counts of furnishing zolpidem, a controlled substance.
Sharper was told he couldn't later change his mind and withdraw the California plea and that it would stand even if deals in other states collapse.
"To use the vernacular, do you understand that this is a final answer?" Judge Michael Pastor said.
"Yes, sir," Sharper replied.
Billeaud reported from Phoenix.