It was Brian Dumoulin's first season with the Los Angeles Kings, after he spent the 2024-25 season with the Anaheim Ducks and New Jersey Devils. After that season, in the offseason before the 2025-26 season, he signed with the Kings for 3 years at $4 million. Brian Dumoulin's contract drew criticism similar to Cody Ceci's, due to his age. 

In his first season with the Kings, Dumoulin played in all 82 games, scoring 2 goals, tallying 15 assists for 17 points, while averaging 17 minutes a night. Brian Dumoulin spent most of his season playing alongside Cody Ceci. While at times the Kings were okay with them as a pairing, in the playoffs, they were targeted by the Colorado Avalanche, which gave them strong offensive chances when Ceci and Dumoulin were on the ice. 

Individually, Dumoulin also struggled, leading his team in giveaways with 94, most of them in the defensive zone. While he did lead the Kings' defence in giveaways, he was ranked 2nd in takeaways, so Dumoulin would often win the puck back if he gave it up. 

Another individual aspect that puts Dumoulin in a positive light is that when he was not playing with Cody Ceci, he played better; when he played with a different defence partner, his on-ice goal share was the best on the Kings. But with the Kings having them as the 3rd pairing, Dumoulin would not be able to play his absolute best hockey in terms of statistics. 

Overall, Dumoulin's first season with the Kings wasn't the greatest, but he showed flashes of high-quality skill. If he cannot play with Cody Ceci next season, his end-of-season numbers may look stronger. However, as an individual player, Dumoulin showed he can still perform strongly for the Kings. Next season, Peter Laviolette may choose to separate the pairing to improve the Kings' defensive core.