The 28-year-old had spent the past five-plus seasons with the Montreal Canadiens, recording 194 points in 360 games and helping lead the team to a Stanley Cup Final appearance this past season.
Danault was the consensus the top centre available in free agency this summer, lauded for his defensive play and strong penalty killing ability. He finished top-seven in Selke Trophy voting for a third consecutive season in 2020-21, adding five goals and 19 assists in 53 regular-season games.
His new annual salary cap hit is $5.5 million, a significant raise for a third-line centre, after coming off a three-year, $9.25-million contract with Montreal.
Los Angeles has won just a single playoff game since hoisting the Stanley Cup in 2014 but the team appears on the verge of returning to the post-season thanks to the work general manager Rob Blake has done.
The Kings also have Anze Kopitar, Gabriel Vilardi and 2020 second-overall pick Quinton Byfield down the middle, plus they have consistently been one of the teams involved in trade rumours around Buffalo Sabres star centre Jack Eichel.