Officers booked Leaf into the Cascade County Detention Center about 1 p.m. Friday, the Great Falls Tribune reported. Leaf posted a $76,000 bond later that day and is now free.
The former San Diego Chargers quarterback is expected to make his first court appearance Monday in relation to Friday's arrest.
He released a statement Friday evening through his publicist.
"I've made some mistakes, and have no excuses," Leaf said in the statement. "I am using the tools I've learned to move forward rather than backwards, and will be open to talking about the details in the days to come. I am confident that there will be further understanding when the facts are revealed, and feel very blessed for all of the support, especially from my friends and family."
Leaf led Washington State to the 1998 Rose Bowl and was the No. 2 pick in the 1998 NFL draft. He played four seasons in the NFL, mostly with the Chargers.