Channing D. Phillips, nominated for U.S. Attorney for the District, center, appeared with U.S. Attorney Kenneth L. Wainstein in a 2005 news conference. (Robert A. Reeder/The Washington Post)

As spokesman and counselor for a succession of top federal prosecutors in Washington from 1997 to 2010, Channing D. Phillips grew adept at delivering bad news.

Phillips, 57, the Obama administration’s choice to serve as the next U.S. attorney for the District, will need to draw on that skill as the 350-lawyer office concludes its troubled and lengthy campaign-corruption investigation of former D.C. mayor Vincent C. Gray (D).

Current and former Justice Department colleagues say Phillips is perhaps perfectly suited to one of his first challenges: upholding the office’s integrity and authority as it extricates itself from political and legal criticism of its handling of the Gray case. The investigation has lingered for more than five years, and Gray’s allies blame it for his 2014 loss in the primaries as he sought reelection.

Mary Patrice Brown, former chief of the prosecutor’s office’s criminal division and later head of the Justice Department’s disciplinary unit and a top criminal division deputy, said after working for nearly two decades with Phillips, “I’ve seen him dozens of times make the hard decisions.”

Brown declined to speculate about how the Gray case should be resolved, but she said that, in general, “one of the hardest things to do is to decline a case . . . and these are things you need to be decisive about, forthright about.”

Brown, co-chair of the O’Melveny & Myers law firm’s white-collar defense practice, added: “It may be unpopular, but there’s only one rigid bone in his [Phillips’s] body, and that is to do the right thing at all times. Maybe that comes from being the son of a minister, but that is how he is.”

Phillips was born in the District, the eldest child of Shaw clergyman and politician Channing E. Phillips, who at the turbulent 1968 Democratic National Convention became the first African American to be placed in nomination for president by a major political party.

District delegates named Phillips, who was a Democratic national committee member and the senior minister at Lincoln Temple Congressional Church, as a favorite-son candidate in place of the slain Robert F. Kennedy.

Despite his family history and his father’s association with civil rights and housing issues, the younger Phillips has not been viewed as a political player and “has no deep ties” to the District’s political establishment, said longtime family friend David Marlin. That distance may help him bring what several of his supporters call a “fresh eye” to the Gray case.

Yet with only 15 months before a new president takes office, Phillips risks being seen as a caretaker appointee, whose decision in the Gray matter may inevitably be criticized whatever he concludes.

“I wish him luck, because he’s going to need it,” said Joseph E. DiGenova, who as U.S. attorney from 1983 to 1988 battled publicly with the District’s elected leadership in obtaining convictions for corruption against two of Mayor Marion Barry’s deputy mayors.

Phillips was named interim U.S. attorney, allowing him to take office Oct. 19 pending Senate confirmation within 120 days. If the Senate does not act, the U.S. District Court could appoint him to the post .

Unlike many nominees for U.S. attorney, Phillips has not tried a long list of high-profile cases, but his uncommon experience has won him support from judges throughout the court as well as from U.S. attorneys appointed by Republican and Democratic presidents.

As a career prosecutor since 1990, Phillips’s strengths have been his counsel and management leadership at both the Washington federal prosecutor’s office — the largest in the country — and top levels of the U.S. Justice Department. Likewise, while he was best known as their public spokesman, Phillips’s most attentive audience has been the U.S. attorneys he advised behind the scenes, one of whom called him the “backbone” of the office.

Hired by Eric H. Holder Jr., now a former attorney general, when Holder was U.S. attorney, in 1994, Phillips rose from line prosecutor to special counsel, chief of staff and principal assistant for the next four top prosecutors, including the District’s first female U.S. attorney, Wilma A. Lewis. Phillips served under Roscoe C. Howard Jr., Kenneth L. Wainstein and Jeffrey A. Taylor before serving as acting U.S. attorney in 2009 and 2010.

Phillips developed and led a diversity management effort at the Justice Department in 2010. After finishing that role, he became senior counselor to Holder and to Holder’s successor as head of the Justice Department, Attorney General Loretta Lynch. He focused on criminal justice matters, including reform efforts, review of federal death penalty-eligible cases and relations with the 94 U.S. attorney’s offices.

“He’s not the loudest guy in the room. . . . [But] when he talks, people listen,” said Monty Wilkinson, head of the Justice Department’s Executive Office for U.S. Attorneys.

Wilkinson has known Phillips since 1989 when the pair clerked for D.C. Superior Court judges before overlapping at the Justice Department’s organized crime and racketeering division, where Phillips spent four years.

Phillips’s learning curve will not be steep. He has worked closely with the office’s veteran prosecutors, including his immediate predecessors, former U.S. attorney Ronald C. Machen Jr. and his top deputy, acting U.S. attorney Vincent H. Cohen Jr. Machen and Cohen ran the Gray investigation and also got their start under Holder in 1997.

Phillips declined through a spokesman to comment about his selection pending confirmation by the Senate.

But Wilkinson called his friend and colleague “well grounded” if not laid-back. He said he’s a jazz aficionado, a die-hard fan of the University of Virginia and was a season ticket holder of the Washington Wizards for several years.

“He’s devoted his career to public service, in particular to the Department of Justice and the community in which he grew up,” Wilkinson said. “He’s the kind of guy folks have wanted on their staffs because of this — he’s a humble man, but extremely smart with extremely good judgment, and very loyal.”