Speaking Thursday at a Democratic National Committee fundraiser in Atherton, Calif., the president was acknowledging several people in the room when he singled out Harris as "brilliant ... dedicated and ... tough, and she is exactly what you'd want in anybody who is administering the law, and making sure that everybody is getting a fair shake."
"She also happens to be by far the best-looking attorney general in the country," he said to laughter. "And she is a great friend and has just been a great supporter for many, many years."
Some commentators called Obama's remark sexist, and said it is indicative of a double standard under which women's professional success depends on cosmetic attractiveness.
White House spokesman Jay Carney told reporters Friday the president called Harris when he returned to Washington Thursday night "to apologize for the distraction created by his comments."
Carney said Obama told Harris he "did not want in any way to diminish the attorney general's professional accomplishments and her capabilities."
"And he believes and fully recognizes that the challenges women -- or he fully recognizes the challenge women continue to face in the workplace and that they should not be judged based on appearance."
Carney declined to speculate on whether the president thinks the remark was sexist.