|Birth Date||October 28, 2008|
|Family|| Jennifer Jareau (mother)|
William LaMontagne, Jr. (father)
Unborn sibling (deceased)
William LaMontagne, Sr. (paternal grandfather; deceased)
Sandy Jareau (maternal grandmother)
Unnamed maternal grandfather (deceased)
Unnamed maternal great-aunt
Rosaline Jareau (maternal aunt; deceased)
Unnamed maternal great-grandparents
Spencer Reid (godfather)
Penelope Garcia (godmother)
|Portrayed By||Mekhai Andersen|
Henry was born during the Season Four episode Memoriam, and after the team gets to meet him after finishing a case, JJ asks Reid and Garcia to be Henry's godfather and godmother, respectively. In Normal, JJ brings Henry to the BAU headquarters after the team solves a case, and the team takes turns holding him.
In Amplification, after a homegrown terrorist lethally poisons dozens of Annapolis parkgoers with a modified version of anthrax, JJ becomes concerned after learning a baby was poisoned with anthrax during the Amerithrax attacks and calls William to tell him to keep himself and Henry safe. The call isn't answered, and this worries JJ further. When the case is concluded, JJ most likely lets go of this fear.
In 2011, Henry suffered from a seizure and had at least one hospital visit prior to There's No Place Like Home. He consequently contracted a fever that became worse, culminating in another hospital visit escorted by William. This forced JJ to return home, but due to the severe weather conditions, she still had to stay in Kansas. After the case is concluded, JJ calls Henry and tells him a bedtime story.
In the two-part season finale episodes Hit and Run, he is taken hostage by Izzy Rogers, unbeknown to him. He asks her to play a game of hide-and-seek, to which she tries to scare him by singing "Ring Around the Rosie", then tell him a story about her (presumed) grandfather, who allegedly resembles him and shares the same name, but this ploy fails. When Izzy is later distracted, Henry hides in a closet, hoping to play hide-and-seek with her. Izzy then gets into a struggle with JJ, who emerges victorious. By the end of the episode, he witnessed Will propose to JJ with Rossi and attends the wedding, becoming amazed by a magic trick performed to him by Reid.
In The Good Earth, Henry didn't want to go trick-or-treating because his friends told him that Halloween was the one time that real monsters were among humans. JJ helped him get over his fear by challenging Henry to identify who were real monsters and who were not. By the end of the episode, Henry dressed up as his favorite profiler, his godfather Spencer Reid. He briefly reappeared in The Apprenticeship, attending a bureau softball match with JJ.
In Nanny Dearest, Henry receives a bath from JJ, just before she leaves to investigate a case. Before she leaves, she promises him that she will be back as soon as she can. By the end of the episode, JJ returns home to find Henry already sleeping. As Will approaches her, JJ closes the door to his bedroom, taking one last loving look at him.
Henry briefly reappeared in 200, when Will hands him over to CSU Tech Agent Gina Sharp, who takes care of him as the BAU search for JJ, who had gone missing. In that same episode, it was revealed that, in 2011, he was about to have a sibling, but due to an explosion Michael Hastings intentionally set off, his mother had a miscarriage and the unborn baby died.
- Mekhai Andersen, the child actor who portrays Henry in 100 and onwards, is actually the real-life son of A.J. Cook, the actress who plays JJ.
- His favorite profiler (presumably besides his own mother) is his godfather Spencer Reid (The Good Earth).
- Henry's birthday was confirmed to be October 28, 2008, but in 200, Rossi mistakenly states his birthday as being November 12 while attempting to figure out the four-digit combination code for a secret briefcase in JJ's office. This was indefinitely a mistake on the writer's part.