Chicago Fire’s Matt Casey and Sylvie Brett’s Relationship Timeline

The One Chicago universe is packed with couples fans can’t help but love, and Chicago Fire’s Matt Casey and Sylvie Brett, a.k.a. Brettsey, are no different. Like many fictional duos before them, Casey (Jesse Spencer) and Brett’s (Kara Killmer) road to romance was full of bumps and bruises. The twosome met in season 3 when Killmer joined the cast as paramedic Brett, working alongside firefighter Casey’s then-fiancée, Gabby Dawson (Monica Raymund). Casey and Brett had an instant friendship, but it wasn’t until his relationship with Dawson ended in season 7 that Brett came into view as Casey’s perfect match. Casey proposed to Brett during the season 11 finale, and the pair began planning a season 12 wedding. “Shooting the Brettsey wedding episode has been bittersweet — more sweet than bitter,” Killmer said in a February 2024 behind-the-scenes video via Entertainment Weekly. 'One Chicago': A Guide to How Dick Wolf Characters Are Related Spencer, who was a regular on the show from season 1