It took longer than the Los Angeles Kings had hoped, but Vilardi made an instant impact in his first NHL game, when he scored a goal 10 seconds into his first shift on Feb 20, 2020.

The Kings selected Vilardi, a center from Kingston, Ontario, with the No. 11 pick in the 2017 NHL Draft, and signed him to a three-year, entry-level contract on March 1, 2018.

However, a chronic back injury cost Vilardi much of the 2018-19 season and limited him to four games with Ontario of the American Hockey League; he was unable to play for Canada at the 2019 IIHF World Junior Championship.

Vilardi was healthy for the beginning of the 2019-20 season and was assigned to Ontario, where he scored nine goals in 32 games before the Kings called him up. He had barely stepped on the ice for his NHL debut before taking a wrist shot that beat Florida Panthers goalie Sergei Bobrovsky. Vilardi also had an assist in Los Angeles' 5-4 victory.

Vilardi played 10 games in his rookie season, finishing with seven points (three goals, four assists), leaving the Kings and their fans eager for more.

Vilardi was traded to the Winnipeg Jets in the deal that sent Pierre-Luc Dubois to the Kings on June 27, 2023, coming off 41 points (23 goals, 18 assists). He signed a six-year, $45 million contract ($7.5 million average annual value) with the Jets on July 18, 2025, avoiding an arbitration hearing, after setting NHL career highs in goals (27), assists (34) and points (61) in 71 games and four points (one goal, three assists) in nine Stanley Cup Playoff games.