In Season 1, Joel is introduced as the husband of Julia Braverman-Graham, as well as the father of their only daughter, Sydney Graham. He is a stay-at-home-dad while she works as a corporate lawyer. He is very close to Sydney, and Sydney openly prefers Joel since he is always at home. Soon, he becomes close to Raquel, a mother on the PTA, and Julia becomes jealous. When Julia fears that he will cheat on her, they share a tearful moment where Joel assures her that he would never cheat on her.
Although Joel occasionally struggles with his role as a stay-at-home dad, especially since he had a career as a successful contractor before Sydney was born, he is supportive of Julia and loves being a father.
In Season 2, Joel and Julia try to have another baby when Julia realizes that she wants more children. Joel at first is reluctant because he fears that he'll be saddled with all the hard work while Julia resumes her career, but agrees on the condition that there be room for him.
After months of trying, Joel fears that he is the problem and goes to see a doctor about it. He is relieved when he discovers that he is fine, but Julia later finds out that she has a condition that makes it difficult to get pregnant. Searching for answers, they turn to adoption.
In Season 3, Julia meets Zoe, a young girl who is pregnant but wants to give up her baby. Though Zoe initially doesn't want Joel or Julia to adopt her baby because she wants a closed adoption, she eventually realizes that they would be great parents to the baby. Joel builds the new baby's room, and he and Julia anxiously wait for the birth of their child. However, after Zoe gives birth to a baby boy, she decides to keep the baby, which crushes Julia. At the end of Season 3, Joel and Julia decide to adopt Victor Graham, a 9-year-old boy who's mother is imprisoned.
In Season 4, Joel struggles to raise Victor, who is cold against him and Julia. Julia and Joel are unsure how to parent him due to his behavior. Julia wants to reconsider the adoption, and puts off finalizing the adoption, which upsets Joel. Eventually, however, they decide to adopt him, and the whole family joins them in the courthouse.
Joel also takes a job as a contractor for a couple of different buildings. This causes a rift in his relationship with Julia, especially when she quits her job, because he feels that she doesn't respect him and his work the way that he did with her.
In Season 5, Joel and Julia's marriage is on the rocks. Joel becomes jealous of Ed, a parent whom Julia has formed a close friendship with. When Julia reveals to Joel that Ed kissed her, Joel decides to move out, and they separate. Julia tries to fight for their marriage, but Joel says that there's nothing left to fight for because she's the problem.
In Season 6, Joel realizes that he still loves Julia and tries to fight for her. Julia is wary of giving him another chance, as she fears that he will turn his back on her again. He and Julia both agree to divorce and split up their assets, with Julia getting the house, but sharing joint custody of the kids. Eventually, however, they sleep together before signing their divorce papers, leading to them reconciling. Although they still have some problems to work out, it appears that they come out stronger than ever.
In the series finale, Joel and Julia decide to adopt Victor's biological half-sister. In the flash forward scene, Joel, Julia, Victor, and Sydney are seen celebrating Christmas with Victor's sister and another baby boy, who presumably is their biological child.
- Jaeger is one of the twelve "Friday Night Lights" cast members to star on "Parenthood." The eleven others are Michael B. Jordan (Alex), Matt Lauria (Ryan York), Scott Porter (Peter), Derek Phillips (Billy), Minka Kelly (Gaby), Jurnee Smollett-Bell (Heather), Jeff Rosick (student), Angela Rawana (therapist), Jesse Plemons (Landry Clarke of Crucifictorious), Stephanie Hunt (Devin Corrigan of Crucifictorious), Jimmy Adler (Kurt Kaster of Crucifictorious).
- Jaeger appeared on Parenthood creator, Jason Katims', other TV show, "Friday Night Lights" as a Under Armour salesman selling uniforms to Coach Taylor. He was uncredited.