Detective William LaMontagne Jr. was played by Josh Stewart. He used to work for the New Orleans Police, taking after his father, who died in Hurricane Katrina.He is first seen in the second season episode 'Jones', investigating a case which belonged to his father. He calls in the BAU to assist him. An obvious attraction between William and JJ (A.J. Cook) is seen in that episode. After the team closes the case and is ready to leave New Orleans, JJ gives him her number. Later, in the third season, it is revealed that they have been dating ever since.In the third season episode 'In Heat', William joins the BAU team in Miami to investigate a serial killer who appears to have a conflicted sexual identity in which William's partner was also a victim. JJ doesn't want to reveal their relationship to the rest of her colleagues, which offends and frustrates William. They even break up very briefly, but then JJ admits to herself and to William that she is not ashamed by their relationship; she is just afraid of making it real by revealing it openly, and thus risk losing it. They then make up and stay together.In the next episode, JJ calls William and tells him she is pregnant. In the season finale, William tells the team about the pregnancy and how he has proposed to JJ, but she cuts him off and says there are kinks to work out. Later in the episode, she receives a package from William: it contains his detective's shield, indicating he would be willing to give up his job to be with her and their child. It is never explicitly stated that they marry, but the two are shown together when their son Henry is born. William and JJ will then ask Garcia and Reid to be Henry's godparents. They also appear together in season five, at Haley Hotchner's funeral.The two are seen together at the funeral for Emily Prentiss when it is thought she had died on the operating table. There is also an episode where the two, seen living together, are arguing and JJ later states she and will are going through a rough patch but will work it out. In the Season 7 finale, Run, Will gets put in a dangerous situation, ending with him getting shot. When all is said and done JJ tells him to ask me again and Will once again proposes. JJ says there's a chapel in the church but Will tells her she's the one that's supposed to be wearing a gown and so they agree to go to the courthouse on Monday instead. Overhearing the conversation, Rossi, who is with Henry, decides to plan them a wedding the next day. The episode ends with everyone dancing. Show less «