The defending Stanley Cup champions also dealt defenceman Oleg Tverdovsky to the Kings for forward Eric Belanger and defenceman Tim Gleason.
The 19-year-old Johnson, a sophomore at Michigan, twice in the past year has turned down offers from the Hurricanes to turn professional, prompting Carolina general manager Jim Rutherford to entertain trade offers.
Rutherford said he had decided a week ago that he would not trade Johnson, but then talks with the Kings picked up.
"We just felt that we're getting a very good NHL defenceman in Tim Gleason," Rutherford said. "He's still a young guy, he still has an upside, and both of those players will come in and be with us now, instead of waiting for the development of Jack Johnson, who in my opinion is going to be a very, very good, if not great, NHL player."
Carolina has been in need of defensive help after losing defenceman Aaron Ward to free agency in the off-season and learning it would be without Frantisek Kaberle for up to six months while he recovers from shoulder surgery.
In Gleason, they get a former first-round pick who had two goals and 19 assists in 78 games during his sophomore season with the Kings. The 23-year-old, who will make US$1.2 million this season, was acquired by the Kings from Ottawa for Bryan Smolinski at the trade deadline in 2003.
Belanger, 28, set career-highs with 17 goals, 20 assists and 62 penalty minutes last season, his fifth with the Kings. He will make $1.3 million this year.
"Eric and Tim strengthen the balance of our team," said Rutherford.
Tverdovsky, 30, played in 72 games last season, scoring three goals with 20 assists and 37 penalty minutes. He has $5 million and two years left on his contract.
The Kings will be his fifth team in his 12th NHL season. In 687 career games, he has recorded 77 goals and 236 assists.