Derek and Jackson's relationship was considered to have been a rocky one but one relationship that evolved to that of friends and mentor/mentee. Derek and Jackson first met in Season 1's Second Chance at First Line, when Jackson began researching how his classmate and teammate Scott McCall gained newly-demonstrated athletic skills, unaware it was a result of his transformation into a Beta Werewolf, but they only traded looks with each other. The two would not have their first conversation until Magic Bullet, which ended with Derek accidentally clawing the back Jackson's neck while he was suffering from Wolfsbane poisoning.
Throughout Season 1, Jackson attempted to figure out what was Scott's secret as well as trying to understand what connection that he had with Derek. Eventually, Jackson realized that both Derek and Scott were Werewolves, and began blackmailing the latter to help him obtain the Bite by theratening to out him as Werewolf to his girlfriend Allison Argent and her family of supernatural Hunters. Believing Jackson would put them all in danger against the Argents, Peter Hale, the Alpha who bit and turned Scott, instructed his nephew Derek to bring Jackson to the Hale House ruins and kill him there. Fortunately, Scott arrived in time to save his fellow co-captain, though he sustained several gunshot wounds in the process.
Scott managed to convince Derek to help him take down Peter for good and they battled against the Alpha at the Hale House but he proved to be more than a match for them and transformed into his Beast Alpha form. Stiles and Jackson arrived and threw Molotov Cocktails to set the Alpha on fire and he returned to his human form, badly burned. Derek approached him and, denying Scott the chance to kill Peter and be cured of his lycanthropy, slashed Peter's throat, killing him and usurping his Alpha powers. Hours later, Jackson showed up at the Hale House and demanded Derek to be turned into a Werewolf because he had a role in Peter's downfall and believed it was his turn to get what he wanted. Sick of Jackson and the problems that he caused in his quest to become a Werewolf, Derek ultimately relented and bit him, though he hoped the Bite would kill him so he wouldn't be a threat for the supernatural community of Beacon Hills again, but he also knew if Jackson successfully turned into a Werewolf, it would help him build a pack for himself.
In Season 2's premiere, Derek attempted to recruit Jackson into his pack, an offer that Jackson immediately refused since he had his own agenda, which didn't involve "running through the woods and howling at the moon" with Derek and Scott. Their attention shifted to a strange black substance that Jackson was releasing from his facial orifices, seemingly a result of his body fighting against the transformation but Derek had no explanation for that or what it could mean. Not long after, a new, mysterious, reptilian shapeshifter known as a Kanima showed up in town and began killing numerous former members of the 2006 Beacon Hills High School swim team, forcing Derek to find out who it is. Jackson and Lydia were the only two suspects but while Jackson was paralyzed by Kanima Venom, Lydia proved to be unaffected by it, leading Derek and his newly-formed pack to believe she was the Kanima.
However, they were proved to be wrong and Jackson was revealed to be the Kanima while Lydia proved to be immune to the supernatural due to her yet-unknown Banshee nature. Although Derek strived to kill Jackson to prevent him from killing more people, he reluctantly agreed with Scott to save him rather than kill him but he proved to be too strong and dangerous to be stopped, not even Derek could defeat him despite his Alpha powers. HIs master was eventually revealed to be Matt Daehler, a fellow student who sent Jackson to murder those he blamed for his near-fatal drowning as a child, but shortly afterwards, Gerard Argent, the Argent Family patriarch, drowned Matt and took control of Jackson to use him against those he deemed responsible for the death of his daughter Kate Argent, particularly Derek and his pack.
During the final battle between the Kanima and the Beacon Hills Werewolves, Gerard attempted to make Jackson transition into his Alpha form so he would become more powerful but their connection was broken when Gerard rejected his transformation into a Werewolf after forcing Derek to bite him as a result of the Mountain Ash pills that Scott tricked him into consuming. Stiles arrived, along with Lydia, who used the key Jackson gave to her to remind him of his identity and snap him out of his Kanima trance, before he allowed Derek and Peter to kill him so nobody else would die. Jackson died for a few moments but the love that he and Lydia felt for one another allowed him to be reborn as the Werewolf he was meant to be, albeit one who retained some Kanima abilities.
At some point between the four months that passed between Season 2's Master Plan and Season 3's Tattoo, Jackson moved to London with his parents to start over, but not before Derek taught him how to remain human during Full Moons so he wound not harm anyone else again.
Throughout Teen Wolf Edit
In Second Chance at First Line, Derek, who had just been released from jail after it was confirmed he wasn't the killer of his sister Laura Hale as Scott McCall and Stiles Stilinski incorrectly assumed, was standing in Beacon Hills High School's lacrosse field to make sure thatnewly-turned and fellow Beta Werewolf Scott did not play the game as he demanded, out of fear he would expose the Werewolf community of Beacon Hills. Instead, he found Jackson, one of Scott's classmates and teammates, picking up one of Scott's gloves that he left on the ground after he left at the end of the game to hide his transformation into a Werewolf from all his teammates, friends and othercitizens that came to watch the game. Jackson found Derek lurking in the shadows and the two stared at each other for a long moment until Derek turned around and returned to the Hale House.
In Magic Bullet, Derek, feeling woozy and weak due to being shot the previous night by Kate Argent with a rare strain of Wolfsbane called Nordic Blue Monkshood, wandered through the high school in search of Scott. He ran into Jackson first and he demanded to know where Scott was, only for Jackson to arrogantly question him why he should tell him where Scott was. Wanting to make this conversation short before he accidentally hurt someone, Derek replied it was because he was asking politely but Jackson, not impressed by the older man's "tough guy" attitude, persisted he would only tell Derek where Scott was if Derek told him the kind of steroids he had been selling to the young Werewolf, believing his new incredible athleticism to be from taking steroids. However, Derek, tired from this conversation, resolved to finding Scott by himself, only for Jackson to begin getting frustrated and grab Derek by his leather jacket, insisting they weren't done talking but Derek fought back and clawed the boy's back of the neck with his claws before he ran away. Unbeknownst to either at the time, Derek exposed Jackson to the same Wolfsbane species he was exposed to and unintentionally shared with him some of his memories of witnessing the Hale House Fire from the outside.
In The Tell,
In Co-Captain, Jackson was working out in the Boys' locker room at the high school, pushing himself to the limit, until his music was mysteriously turned off. He noticed Derek sit in a bench and the Werewolf complimented Jackson's choice of music before he pulled out one of his own, claiming he hadn't heard it for a long time. Half-confident half-afraid, Jackson challenged Derek to come at him and stated he was not afraid of him but Derek smirked and remarked he could tell Jackson was afraid and how Jackson hadn't had a single day in his life where he hadn't afraid of something. Derek offered Jackson the chance to be like him, implying he would help him become a Werewolf, and took him out of the high school. Unbeknownst to either of them, they were being observed by Kate Argent, who mistakenly inferred that Jackson was the second Beta Werewolf working with Derek.
The duo arrived at the Hale House, where Jackson showed hesitation and concern to whether he should go in or not, but Derek put his hand on Jackson's shoulder and guaranteed him that he would have everything he wanted inside the house. Slowly and reluctantly, Jackson opened the door and became surprised to see the house's interior as he told Derek it was the same house that he dreamed for several weeks after Derek clawed the back of his neck with his wolfsbane-coated claws and affirmed he could remember the staircase, the walls and everything else related to the house. However, when Jackson noticed there was nobody else there and Derek closing the door, he questioned if no one else was there and no one else was coming and Derek nodded his head in the negative before he extended his claws, revealing he brought Jackson there to kill him. Afraid of dying, Jackson begged Derek to spare him and swore he would maintain Derek and Scott's supernatural identities a secret. Jackson cried and expressed he didn't deserve such punishment but Derek stated he believed the otherwise and insisted nobody else would be coming to save. He shouted "There is a reason, no one cares that you drive an expensive car. No one cares that you have perfect hair. And no one CARES... that you're captain of the lacrosse team."
Suddenly, Scott's voice was heard from the top of the staircase and he corrected Derek, saying Jackson was co-captain of the lacrosse team. He leaped the staircase in a single bounce and landed between Jackson and Derek, fully wolfed-out. Derek growled menacingly at Scott and ordered him to move out of the way but when Scott stood his ground and refused, Derek complied with the younger Beta's persistence and threatened to kill him too. The two were ready to fight until the sound of a flash-bang arrow being fired led Derek to yell "COVER YOUR EYES!" and the arrow blinded Scott and scared Jackson so much that he crawled away with no injuries while Scott was dazed and left in a vulnerable position to be shot with several bullets laced with Wolfsbane, leading Derek to help Scott escape through the back of the house while he allowed himself to be captured by Kate and the other Hunters.
In Code Breaker, Stiles and Jackson drove through the woods in Jackson's Porsche and arrived in time to witness Derek and Scott's battle against Peter, who was the Alpha Werewolf who turned Scott and who was shifted into his monstrous Alpha form. Stiles threw one Molotov Cocktail at the Alpha but the beast easily caught the beaker in mid-air, scaring and frustrating Stiles. Scott tossed Allison her bow and she shot an arrow at the beaker, breaking it and the flammable content burned Peter's arm. Jackson noticed he had a second cocktail in his hand and, without further ado, hurled it at the Alpha's body, setting the beast on fire. The beast still attempted to reach Allison and take her down with him but Scott delivered a kick to his Alpha's face, driving him away from Allison as he shifted back to his human form and collapsed on the floor, burned.
Scott and Allison briefly shared a kiss and Allison told Scott that she loved him, forgiving him and accepting that his lies throughout the season were meant to shield and protect her from the supernatural. Their moment was interrupted when they noticed Derek heading toward his badly-burnt uncle and standed over him, leading Scott to realize what Derek was about to do. Scott yelled at Derek to stop and asked him to allow him to kill Peter because he believed if he killed the Alpha who turned him, he would be cured of being Werewolf. Conflicted between allowing Scott to kill Peter like he promised him and killing Peter himself and avenging his sister Laura, Derek hesitated for a few moments and Peter, despite in his weak condition, growled that he could smell that Derek had already decided. Just when Peter's eyes began glowing bright Alpha red, Derek slashed his throat, becoming the new Alpha and leaving Scott as a Werewolf.
Later on, Jackson showed up at the Hale House and saw Derek on the top of the staircase. He reminded Derek that he helped him and the others take down Peter and if Derek had new Alpha powers, it was because Jackson had a role in it; so now it was his turn to be rewarded. After some reflection, Derek leaped the staircase and landed in front of Jackson as he flashed his Alpha eyes at him and extended his fangs to bite him.