Shepard, 65, who police said had a blood alcohol level of .175 when he was arrested last month, reportedly told a judge Wednesday, "I never intend to drive under the influence again ... It's not worth it."
Police said they pulled Shepard over for driving 46 mph in a residential area and suspected he was intoxicated.
The longtime beau of actress Jessica Lange wrote the plays "Buried Child," "True West" and "Kicking a Dead Horse," and has appeared in the films "Don't Come Knocking," "The Notebook," "Swordfish" and "The Right Stuff."
TMZ said Shepard was fined $600 plus court costs, placed on 24 months court supervision and ordered to complete an alcohol treatment course and 100 hours of community service as part of his plea deal.