Joshua Michael Beckstead pleaded guilty in a Casper, Wyoming federal court Thursday.
Beckstead was in jail in Utah for allegedly passing forged checks.
Last May, a judge allowed him out to go to the dentist. He never showed up to the appointment or returned to jail.
His robbery spree started the next week, when he held up a credit union in Ogden, it ended up spanning four states.
He'll be sentenced February 27th.