Fisk, 64, was sentenced to one year of court supervision and must pay $1,250 in court costs. He also must undergo a drug and alcohol evaluation and counseling.
Fisk's attorney, Stephen White, said in Will County court that Fisk wanted to accept responsibility for what he did.
"He stepped up to the plate," White said.
New Lenox police found Fisk unconscious in the truck on Oct. 22 and said there was an open bottle of vodka on the floor. New Lenox is about 35 miles southwest of downtown Chicago.
Fisk became part of an unforgettable baseball moment while playing for the Boston Red Sox when he belted a 12th-inning home run that won Game 6 of the 1975 World Series. He played 11 seasons with the Red Sox and 13 with the Chicago White Sox.