A source did not cite a reason for Drew's decision to transfer but did say the junior left campus Friday morning, roughly 48 hours after recording nine assists in 19 minutes in North Carolina's 106-74 victory over Boston College.
In a statement issued later in the day by the school, Drew said he was leaving because "it's in my best interest to continue my education and basketball career elsewhere."
Drew did not indicate where he might play next. If he transfers to another Division I school, Drew will have to sit out a year, and he would have one season of eligibility remaining.
Coach Roy Williams said at a news conference that Drew's father -- Atlanta Hawks head coach Larry Drew -- informed him of his son's decision to leave in a phone call Friday morning. Williams said he was "shocked" by the news.
"Basically there was no arbitrating, there was no trying to see if we could rectify anything," Williams said Friday afternoon. "That was the decision that was made and he thought it was in Larry's best interest."
The Hawks coach said while he made the call, he was just relaying his son's wishes.
"He made the decision. I did speak to coach Williams," Larry Drew said. "I thought it was important we did it in a very tasteful manner and we did that. My son issued the statement and it came from him. He clearly stated that his family has his support."
Drew essentially has shared the point guard position this season with freshman Kendall Marshall; he lost the starting role to Marshall in mid-January.
As a result, Drew's playing time, scoring and assists have dropped from last season -- minutes down from 28.8 to 22.8 per game; scoring from 8.5 points to 4.4; and assists from 5.9 to 3.9.
However, he's had some of his better floor games in the Tar Heels' past three games, all victories, racking up 19 assists and only two turnovers while playing fewer minutes than Marshall.
Drew was a lightning rod for fan criticism last year, when the Tar Heels failed to earn an NCAA tournament berth.
"It is unfortunate my career didn't meet expectations in Chapel Hill," Drew said in the statement. "However I do look forward to continuing my collegiate and athletic career in the near future."
North Carolina is 16-5 overall after winning nine of its last 10, and 6-1 in the ACC, second behind No. 5 Duke. The Tar Heels (T-23 AP) are on the verge of re-entering the ESPN/USA Today coaches' top 25 after being ranked ninth in the preseason.
North Carolina hosts Florida State on Sunday, then travels to Duke on Wednesday night.
Pat Forde is an ESPN.com senior writer. Information from The Associated Press was used in this report.