 -- Attorney General Eric Holder, the first African-American to be the nation's top cop, announced today that he is resigning.

President Obama made the official announcement at the White House alongside Holder at the White House this afternoon.

“Through it all he's shown a deep and abiding fidelity to one of our cherished ideals as a people and that is equal justice under the law,” Obama said.

Speaking in the East Room of the White House, the president praised Holder for doing a “superb job,” ticking off his impressive work to root out corruption and fight violent crime, lower the incarceration rate and protect civil rights.

“It’s a pretty good track record,” Obama said.

The announcement comes after his nearly six years at the helm of the department that were marked by both highs and lows for a man who came in to revamp what many considered a demoralized and scandal-plagued institution.

Under Holder's leadership, the Justice Department saw "historic gains in the areas of criminal justice reform and civil rights enforcement," particularly on the issues of gay rights, sentencing reform and voting rights, and in the coming weeks Holder is expected to impose new curbs on racial profiling in law enforcement, a department official told ABC News.

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In a recent interview with ABC News' Pierre Thomas, Holder, 63, described his time leading the Justice Department as "demanding" but "the honor of my professional life," serving the American people.

"I hope I've done a good job," the native New Yorker said. "I've certainly tried to do as good a job as I can. There are sacrifices that I've had to make, that my family has had to make."

Holder became a lightning rod for Republicans, who held him in contempt of Congress for refusing to hand over documents related to the Fast and Furious gunrunning scandal. An independent inspector general's investigation cleared Holder of any wrongdoing in developing the tactics or cases behind Fast and Furious.

In addition, Holder was forced to revise how the Justice Department handles journalists after an uproar over the department's secret seizure of reporters' phone records and the department dubbing one journalist a "criminal co-conspirator."

Among his other "key accomplishments," according to the Justice Department, are his declining to defend the Defense of Marriage Act, which barred the federal government from recognizing same-sex marriages, and extending federal benefits to same-sex couples. The department also says Holder has been "vindicate[d]" over the use of federal civilian courts to prosecute terrorism suspects, and Holder recently said that if 9/11 mastermind Khalid Sheikh Muhammad and his co-conspirators had been prosecuted in Manhattan, as he originally planned, they would already have been convicted and sentenced.

Holder will stay on as attorney general until a successor is confirmed by the Senate, potentially into the new year.

Holder has been discussing his plans with President Obama for months, and he made a final decision after an hour-long talk with the president over Labor Day weekend, according to the Justice Department official.

Holder has worked at the Justice Department for a total of 26 years, serving at almost every level, according to the department. After working as a career prosecutor on corruption cases and in other positions, President Bill Clinton appointed him to be the U.S. Attorney for Washington, D.C. He served in that role until 1997, when he was appointed Deputy Attorney General, according to the Justice Department.

Holder is married to Dr. Sharon Malone and has three children.

In light of the recent unrest in Ferguson, Mo., after he officially steps down Holder wants "to continue helping to restore trust between law enforcement and minority communities," the Justice Department said. "As a career prosecutor with strong relationships with law enforcement, as well as the first African-American Attorney General who retains deep ties to leading civil rights organizations, Holder is uniquely positioned to help lead such a project.