The Lean on Me star admitted one count of marijuana possession for sale stemming from his arrest in Arizona last year (11) when cops caught him buying 200 pounds (90.7 kilograms) of cannabis from an undercover officer.
He struck a deal with prosecutors and a charge of illegal control of enterprise was dropped in return for his guilty plea.
Hopkins was freed from prison on Tuesday (17Apr12) after he was sentenced to 30 days behind bars, which he had already served following his arrest, and he was also handed three years probation.
He tells TMZ.com, "I am so glad to put this legal battle behind me so that I can begin moving forward with re-establishing my acting career."
The Lean on Me star was taken into custody on Tuesday (13Dec11) after Arizona cops in Maricopa County set up a sting operation and allegedly caught Hopkins buying 200 pounds (90.7 kilograms) of marijuana from an undercover officer before driving off in his car.
According to TMZ.com, officials pulled the actor over and found $100,000 (£62,500) in the star's vehicle. They also discovered an additional 100 pounds (45.4 kilograms) of pot in the actor's apartment.
He is being held on $35,000 (£21,875) bond on two felony counts of possessing, transporting and trying to sell marijuana.
If convicted, Hopkins faces up to five years in prison.