Wolanin was eligible for unrestricted free agency. The Kings announced the deal on Tuesday.
Wolanin, 26, appeared in three games with Los Angeles after the Kings acquired him from the Ottawa Senators on March 29 in a trade for Michael Amadio. Wolanin recorded three assists in 15 games with Ottawa before the deal.
Wolanin has appeared in 61 NHL games over the past four seasons with the Senators and the Kings while also spending time in the AHL. He played three collegiate seasons at North Dakota before signing with Ottawa as a fourth-round pick.
Wolanin is a dual Canadian and American citizen who appeared in 10 games with the United States team at the world championships this year. He led the American defensemen with six points and posted a plus-8 rating while the team won bronze.