"As has been well documented, I smoked pot as a kid, and I view it as a bad habit and a vice, not very different from the cigarettes that I smoked as a young person up through a big chunk of my adult life. I don't think it is more dangerous than alcohol," the president said an interview with "The New Yorker" magazine.
Smoking marijuana is "not something I encourage, and I've told my daughters I think it's a bad idea, a waste of time, not very healthy," Obama said.
Obama's administration has given states permission to experiment with marijuana regulation, and laws recently passed in Colorado and Washington legalizing marijuana recently went into effect. The president said it was important for the legalization of marijuana to go forward in those states to avoid a situation in which only a few are punished while a large portion of people have broken the law at one time or another.
The president said he is troubled at the disproportionate number of arrests and imprisonments of minorities for marijuana use. "Middle-class kids don't get locked up for smoking pot, and poor kids do," he said. "And African-American kids and Latino kids are more likely to be poor and less likely to have the resources and the support to avoid unduly harsh penalties."
He said in the interview that users shouldn't be locked up for long stretches of time when people writing drug laws "have probably done the same thing."
But Obama urged a cautious approach to changing marijuana laws, saying that people who think legalizing pot will solve social problems are "probably overstating the case."
"And the experiment that's going to be taking place in Colorado and Washington is going to be, I think, a challenge," the president said.
Ethan Nadelmann, the executive director of the Drug Policy Alliance praised Obama's words, saying his use of the word "important" about the new Colorado and Washington laws "really puts the wind in the sails of the movement to end marijuana prohibition.
Critics of the new laws raise concerns about public health and law enforcement, asking whether wide availability of the drug will lead to more underage drug use, more cases of driving while high and more crime.