As part of the trade, Carolina acquired forward Erik Cole and a fifth-round selection in the 2009 Draft from Edmonton. The Oilers received a second-round pick in the 2009 Entry Draft from the Hurricanes, which they promptly sent to the Sabres for forward Ales Kotalik.
The trade came one day after the Kings' 5-4 loss at Columbus, a defeat that concluded a 1-4-0 road trip that left the Kings 13th in the West, seven points out of a playoff spot with 19 games remaining.
In 32 games with the Hurricanes this season, Williams, 27, has 3 goals, 7 assists and nine penalty minutes. The 6-foot-1, 195-pounder currently is on injured reserve due to a broken hand sustained Feb. 15; Kings General Manager Dean Lombardi said Williams should be ready to play in a couple weeks.
Williams, a member of Carolina's Stanley Cup-winning team in 2006 and an All-Star in 2007 when he scored a career-high 33 goals, has 124 goals and 316 points in 491 games with the Hurricanes and the Philadelphia Flyers, the team that selected him with the 28th pick in the 2000 NHL Entry Draft. In 42 playoff games, he has 8 goals and 24 points.
Lombardi said Williams brings size, skill and a Stanley Cup pedigree to a young team.
"Justin is only 27, so he can grow with this group," he said. "He's won a Stanley Cup. He gives us more size on the wing and he's a proven 30-goal scorer. We felt that this was a guy who can certainly fit with our mix."
Lombardi said he wasn't concerned about giving up a player who was in the lineup in O'Sullivan in exchange for one who won't be able to play for another couple of weeks.
"We felt that the way Oscar Moller has been playing, we can fill that hole -- and then Justin will be back in a couple of weeks," he said. "We felt we could hold that for now, and then we'd be getting a very good player."
Williams' best seasons came in 2005-06 and 2006-07. He had a career-best 76 points (31-45) while playing all 82 games in 2005-06. The next season, he also played all 82 games and had 67 points, including the career-best 33 goals. He signed a five-year contract with the Hurricanes prior to the 2006-07 season.
Lombardi and Kings coach Terry Murray both were with the Flyers during Williams' time in Philadelphia, and Murray said having some history with a player "gives you a little bit of an edge."
"I've known him for a long time," Murray said. "He was a big part of Carolina's run in the playoffs and the Stanley Cup. He's an exciting guy with great skills. I look for him to be a 30-goal scorer with the Kings
"He's a guy who fits in all situations. He can play on the power play, kill penalties -- he's a real good, all-round fit for the club."
O’Sullivan, 24, had 14 goals and 37 points in 62 games this season. The Kings had acquired O'Sullivan from Minnesota in 2006, and he had 41 goals and 109 points in 188 games with Los Angeles.
O'Sullivan, who signed a three-year contract with the Kings just before the start of the season, admitted the trade caught him somewhat by surprise.
"I think the young group of guys I was with in L.A. had kind of grown up together over the last couple of years, and I think the organization has vastly improved over that time," he said. "But I think at the end of the day, anybody is tradable at any time. I'm just happy that it's to a place that has a lot of history. It's a great hockey market, and I'm excited to come and play there."
Earlier in the day, the Kings re-signed defenseman Sean O'Donnell to a one-year contract and goaltender Erik Ersberg to a two-year deal. The Kings also sent veteran defenseman Tom Preissing, who had gone through waivers unclaimed, to Manchester of the American Hockey League.