Washington (CNN) It didn't happen on 4/20 -- marijuana's high holy day -- but Michele Leonhart is stepping down in mid-May as administrator of the Drug Enforcement Administration, Attorney General Eric Holder said Tuesday.

"I want to express my appreciation to Michele, not only for her leadership of the DEA since 2007, but also for her 35 years of extraordinary service to the DEA, to the Department of Justice and to the American people," Holder said in a statement.

CNN reported earlier on Tuesday the resignation was expected.

Obama administration officials long ago soured on Leonhart, a career DEA agent who broke ground at the agency when she rose into leadership as the first woman to head a field office. In recent years, she has angered the administration for appearing to resist federal rules relaxing enforcement on marijuana as states have moved to legalize the drug for medicinal and recreational use.

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