Ms Biden, 33, who is the daughter of the president-elect’s brother James, was questioned by police in Lower Merion Township, Pennsylvania, in August 2019, after she crashed her car into a tree.
The officer who arrested her noted that she “had difficulty focusing on the conversation” when he questioned her. Ms Biden was also driving without a license, according to The Daily Mail.
Pill bottles for carisoprodol and lorazepam, which are both controlled substances, were found in Ms Biden’s car, while a blood test confirmed they were in her system at the time of the crash.
Following her 3 December hearing, Ms Biden was sentenced to between 20 days and six months of “confinement,” according to Pennsylvania court records seen by the New York Post.
However, Ms Biden negotiated a plea deal with the Montgomery County district judge, which means she will avoid prison time and instead serve 20 days of rehab and the remaining five months of the sentence under probation.
Kate Delano, a spokeswoman for the Montgomery County district attorney, told the Post: “Should she then violate or break the law at any time, then she will be on the hook for the rest of the sentence.”
Mr Biden’s niece will also have to undertake 12 hours of community service and pay a fine of $1,990 (£1,471).
Her license has also been suspended for a year, and she will have to participate in a drugs and alcohol programme.
Although Ms Biden’s arraignment was held one day after the US election on 4 November, a court spokesperson told the Post that the timing was coincidental and auto-generated.
Ms Biden has avoided prison time on two prior occasions. In 2013, Ms Biden was arrested for hitting a New York Police Department officer during a fight with her roommate.
After the case was dismissed, she was allowed to re-plead to a lesser charge of petty larceny and agreed to go to anger management as part of the deal, according to the Mail.
While in 2017, she admitted to spending around $110,000 (£81,345) on a stolen credit card, but avoided going to prison by agreeing to pay off the money and attending an anger management course.
Despite Ms Biden’s previous court visits, Julie Rendelman, a former New York prosecutor who is now a criminal defence attorney, told Law&Crime that her plea deal for the DUI is common.
“In my experience with these cases, I have actually never seen a jail time offer unless the accident resulted in someone being injured,” she said.
Ms Rendelman added: “The plea she received is comparable to other first offence DUI cases in that jurisdiction.”