Jay was a big fan of Cliff Gordon ever since he was kid. In Season 6, Jay had learned that he was really adopted and that Cliff is his real father, which left him very shocked and excited at the thought.
After Nadakhan was defeated, all of the wishes have been undone and Jay has not received his inheritance yet.
The previous Elemental Master of Lightning is Jay’s biological mother; while Jay has discovered that Cliff Gordon is his real father, he does not know that who his biological mother is.
It is unknown whether she is still alive, why she and Cliff had left Jay in the care of the Walker family, or whether Jay will find out about her or if he will ever meet her in future seasons.
Ed is Jay's adoptive dad. Jay is very close to his adoptive father and has inherited his habit of inventing things. In Season 6, when Jay made a wish to Nadakhan he received a letter saying his father passed away and he has inherited his fortune. Immediately, Jay rushed to his parent's home where he called out for his father only for Ed to come out alive and well. Jay was relieved at the news but questioned the contents of the letter; Ed and his wife decided it was time to tell Jay the truth and inform him that he was adopted.
Edna is Jay's adoptive mom. Although he gets annoyed when she tells his friends about their Junkyard, he cares about her very much. Their bond grew stronger at the end of "Snakebit" when Jay invited both his parents to the Destiny's Bounty whenever they want to visit.
Nya is Jay's girlfriend. In the beginning, they barely spoke to one another but Jay started to develop feelings for Nya while she did not return his feelings at first. Though they grew closer and starting dating being shown happy with each other. The two reached a rough patch in Season 3 when Nya started developing affections for Cole causing a rivalry between them which continued in season 4 where all three make up. In Season 5, Jay discovers from a reflection of his "future" that he will get back with Nya inspiring him to pursue her again.
In Season 6, Jay goes through with his attempts using his wishes to try and impress her but in the course of the conflict with Nadakhan, Nya makes it clear to him that they are just friends, much to his dismay.
However, in the Season 6 finale when Nya nearly dies, Jay uses his last wish from Nadakhan to undo the recent events done by the Djinn, which brings her back to life. Nya and Jay reconcile their relationship, sharing a kiss and start to date once more.
Jay is one of Master Wu's students along with the other Ninja. When Jay and the others trained to become Ninja, they showed that they really cared about Wu and glad to have him as their master.
Like the other Ninja, Jay respect Wu who in turn views him as he expressed concern for the latter when he was attacked by Acronix and began to rapidly age due to the affects of the time blade. Along with the ninja, Jay wanted to find his master after he was lost in time with the Time Twins.
In Season 8, Jay and the others were still searching for Wu before dealing with the Sons of Garmadon. They find an infant, whom they take in for some time. After the child has a growth spurt and starts to walk and talk and uses one of their mottos, a shocked Jay is the first to realize the baby is in fact their master de-aged because of the Time Blades. Jay was relieved to hear he would turn back after the blades' effects wears off and happy to have him back.
They have not interacted a lot in the series but they care deeply about each other and have gotten closer as the series goes on.
At first, Kai didn't like the thought of Jay dating his sister due to his overprotective nature but soon came around to the idea.
They are good friends until Season 3 when Nya started developing feelings for Cole which initiated a rivalry between the two which continued in season 4. The two reconcile their friendship during their fight on Chen's Island and Cole even sacrificed himself so that Jay could win the battle.
In Season 6, it is mentioned "On a Wish and a Prayer," that in spite of the previous rift between them that Cole considers Jay to be his best friend. In "Day of the Departed," when Cole was feared lost after facing Yang, Jay broke down and stated he'd give up anything to have Cole back which the latter overheard before revealing himself. Jay and the others were relieved that Cole was safe and human again.
Like all the other ninja he thought Zane was weird but when finding out that Zane was Nindroid, he and the others supported and accepted their friend. They grew close throughout the series, with Jay being distraught by Zane's death after he sacrificed himself to defeat the Overlord.
In Season 4, Jay was looking at his portrait of his friends in sadness and reflecting on his time together with Zane. When Lloyd suggested replacing Zane, Jay heavily protested against the decision to do so but was shocked to learn that his friend was still alive and traveled to Chen's Island to find him. While imprisoned by Chen, Jay was reunited with Zane and was elated to see his friend again and complimented his new form.
As the series goes on they still get along, in season 5 where Jay tried to fix Zane's malfunctioning voice and modifying it for comical purposes.
Lloyd and Jay are good friends. They don't talk much, but as the series go on, they grew closer.
In Season 3, Lloyd introduced Jay to Fritz Donnegan and got him hooked on the character.
In season four, Jay denied Lloyd's offer to go back to the team but still went along with meeting him. Jay had faith in Lloyd as he believed the latter would save him and the others from Chen after they were captured. In Season five, when Lloyd got possessed by Morro, Jay and the other ninja will do everything they can to get their friends back.
In Season 8, Lloyd and Jay hear about the history of The Realm of Oni and Dragons from Mistaké. Jay realizes that Lloyd is part Oni and Dragon and is the only ninja besides Lloyd to know about that. When Mistaké tells Lloyd that the Oni Masks can bring his father back from the dead, he has a sad look on his face, and Jay tries to comfort him by putting his hand on his shoulder.