Trotz, 51, becomes the 17th coach in Capitals history and joins Washington after spending 15 seasons as coach of the Nashville Predators.
"We are extremely pleased to name Brian MacLellan the team's general manager and welcome Barry Trotz to Washington as the Capitals coach," Capitals owner Ted Leonsis said in a statement. "After conducting an extensive search for a general manager, we determined that Brian was the best candidate to help us reach our ultimate goal, winning the Stanley Cup. We have witnessed his abilities firsthand, and we have tremendous respect for how he manages people and situations. We feel he has relevant, in-depth knowledge of the strengths and weaknesses of our franchise and will be forceful in addressing them. Brian always has displayed tremendous professionalism, passion and commitment to the Capitals. He has his own unique approach, and we are confident in his abilities to lead this organization to new heights."
MacLellan, who won a Stanley Cup as a player with the Calgary Flames in 1989, had a 10-year NHL career in which he skated for the Los Angeles Kings, New York Rangers, Minnesota North Stars, Flames and Detroit Red Wings.
Trotz was previously the longest-tenured coach in the NHL and only coach in the Predators history. He ranks third all-time in both games coached (1,196) and wins (557) with a single franchise. He also ranks 15th on the NHL's coaching victories list and fourth among active coaches behind only Joel Quenneville (Chicago), Ken Hitchcock (St. Louis) and Lindy Ruff (Dallas).
"Barry is a highly respected and accomplished coach who brings us a wealth of experience," said Leonsis. "He possesses high character and the exact leadership qualities we look for in the head coach. He was the only coach we coveted, and we feel he is an ideal fit to help lead our club."
Prior to joining the Predators, Trotz spent five seasons (1992-97) as the coach of the Capitals' primary developmental affiliate in the American Hockey League.