By Alex Rogers, TIME

President Obama paid tribute to Attorney General Eric Holder Thursday, as he announced the resignation of the country’s top law enforcement official.

Standing alongside Holder at a White House press conference, the president confirmed that America’s first black attorney general’s would step down from his position as soon as a successor was confirmed by the Senate.

“Bobby Kennedy once said, ‘on this generation of Americans falls the full burden of proving to the world that we really mean it when we say all men are created free and equal before the law,’” said Obama. “As one of the longest-serving attorney generals in American history, Eric Holder has borne that burden.”

Obama credited Holder—who has a portrait of Kennedy on his office wall—as a civil rights defender who spent his career atop the Justice Department reforming the criminal justice code, defending voting rights and supporting the legal rights of same-sex marriage advocates. Obama also thanked Holder for his service under six presidents of both parties, calling the moment “bittersweet.”

Holder said he came to the end of six years leading the Justice Department “with very mixed emotions,” occasionally fighting back tears as he spoke.

“I’m proud of what the men and women of the Justice Department have accomplished,” he added, but said he was “very sad” that he would serve alongside them no longer.

This story has been updated with new information from an afternoon press conference.