Young said he got some "pretty sincere" advice from his doctor and set aside the two-long running vices.
"I think I'm still high from the last 50 years, but I certainly don't miss it at this point," Young joked in an interview with Parade magazine.
Young cleaned up his act amid a still-rigorous schedule of live concerts and recording. His latest album with Crazy Horse, "Psychedelic Pill," was just released, along with his memoirs "Waging Heavy Peace."
Young said he takes breaks when needed and enjoys his downtime at his place in Hawaii.
But he is also not planning to coast for the remainder of his career.
"I want to be a better guitar player and I want to learn how to sing better," Young said, adding: "This is who I am. I never thought about not doing this."