ESPN NFL Insider Adam Schefter confirmed Peterson's hiring of Hardin.
Hardin successfully defended former major league pitcher Roger Clemens against charges that he lied about not using performance-enhancing drugs in testimony he made before Congress.
Peterson was arrested early Saturday morning after an early-morning incident in Houston, where police say it took three officers to subdue him. Peterson, from Palestine, Texas, was released from jail Saturday on a $1,000 bond. The charge is a misdemeanor, and Peterson is due in court on Friday, according to the Houston Chronicle.
Houston Police Department spokesperson Kese Smith said that Peterson would probably end up with a fine because the charge is a misdemeanor.
Peterson took to Twitter on Sunday and cited a Winston Churchill quote.
"'A lie gets halfway around the world before the truth has a chance to get its pants on,'" Peterson tweeted.
The star running back later posted: "Thank you for waiting for the facts. Truth will surface."
Smith said Peterson was at a downtown nightclub early Saturday morning when an off-duty Houston police officer working security asked Peterson and a group of people he was with to leave because the club had closed.
Smith said the man identified himself as a police officer. The officer left to tell other patrons to leave the club before returning to Peterson's group again to tell it to leave.
Smith said Peterson turned around and told the officer that he heard him the first time and pushed the officer in the shoulder, causing him to stumble. The officer told Peterson he was under arrest and to put his hands behind his back. Peterson began yelling, pulled away and "assumed an aggressive stance," so another off-duty officer came to help. Peterson continued to struggle with both, according to Smith.
The 27-year-old player finally was handcuffed with the help of a third off-duty officer, Smith said. Peterson complained of shortness of breath after he was taken to a Houston jail and was examined by Houston Fire Department personnel, who said he was OK.
Peterson's father told the St. Paul Pioneer Press on Monday that the first off-duty officer used "vulgar language" and was "disrespectful" when asking the running back to leave the area.
"Adrian is kind of frustrated because he's the kind of guy who's tried to do the right things in society and he cares about being a high-character guy," Nelson Peterson told the paper. "He has a 9-year-old daughter, so he doesn't want her hearing in the news about how he's being perceived."
Nelson Peterson, who told the paper he was not present at the time of the incident, said Adrian Peterson suffered a black eye in the scuffle. He also told the Pioneer Press that it's his understanding that his son didn't push the officer.
"The officer said he pushed him, shoved him; then why is he not charged with assault?" Nelson Peterson told the paper. "Only charged with resisting arrest. Doesn't make sense."
Nelson Peterson, who according to the Pioneer Press received a 10-year prison sentence for laundering drug money when Adrian Peterson was 13, also told the paper that "Adrian has a high regard for people in the military and the officers that help protect us."
Peterson ran for 970 yards and 12 touchdowns last season before tearing the anterior cruciate and medial collateral ligaments in his left knee on Dec. 24. The injury-shortened season broke a streak of four straight seasons with at least 1,200 yards rushing for the former Oklahoma standout.
Information from ESPN.com NFC North blogger Kevin Seifert and The Associated Press was used in this report.