Los Angeles Police have confirmed Terry Bryant was arrested for grand theft, after the statuette went missing from the Governor's Ball.
The 47-year old was booked and has had bail set at $20,000 (£14,400). He will attend court at a future date.
The statue has since been returned to the best actress winner.
A representative for the actress told USA Today: "Fran and Oscar are happily reunited and are enjoying an In-N-Out burger together".
LAPD said Bryant was a ticket holder for the Governor's Ball, which is the official formal dinner after the ceremony.
McDormand had already had her name engraved on the statue at the ball before it went missing.
The actress was celebrating her win of the award for best actress for her role in Three Billboards Outside Ebbing, Missouri.