"David has successfully completed his rehabilitation," attorney Stanton L. Stein said in a statement released to various press outlets earlier this week.
Duchovny, best known for his roles as Agent Mulder on Fox's "X-Files" and Hank Moody in Showtime's "Californication," voluntarily entered The Meadows, an Arizona treatment center, in late August to undergo a 35-day program.
At the time, it was rumored Duchovny was involved in an extramarital affair with his tennis instructor, but friends of the actor said his addiction centered on Internet porn.
Duchovny is married to actress Tea Leoni. The couple has a 9-year-old daughter and a 6-year-old son.
Stein's statement said the actor is set to begin work on a new movie, The Joneses.