Bearheart Triston Buehlmann was found unresponsive during morning wake-up call, county spokesperson Carolyn Marinan said.
Court records from the past year show Buehlmann was convicted of misdemeanor theft and assault in separate cases. In February, he pleaded guilty to felony marijuana possession and was jailed in May after admitting to a probation violation.
The workhouse is in Plymouth, Minn. A website for the facility on Monday night said visits and phone calls to the men's section were suspended.
The sheriff's office is investigating Buehlmann's death.