Kyle Middleton is one of Jenna's half-brothers, and likely the one with whom she is closest, as the two of them lived together in Toronto. Although initially supportive of Jenna and K.C. raising their son Tyson together, Kyle's eventual frustration with them led to him returning to Alberta. It is unknown whether Jenna currently harbours any resentment towards Kyle for abandoning her.
In Just Can't Get Enough, Jenna is at Clare's house. Clare is doing Jenna's nails, telling her that her older sister Darcy taught her how to do proper manicures. Jenna expresses her jealousy at the fact that Clare has a sister, and mentions that she has three half-brothers.
In Heart Like Mine (1), Kyle stops by the Degrassi car wash as Jenna introduces him to Clare and K.C. Kyle brings up that Jenna talks about K.C. all the time, which embarrasses Jenna.
In Tears Dry On Their Own (2), Kyle is with Jenna at the doctors' after finding out that she is pregnant. When the doctor asks who will be helping with the baby, he says that he will and that their mom and dad are out of the picture.
In Don't Let Me Get Me, Lisa asks Jenna if her brother works, and Jenna tells her he works part-time, but his hours had been recently cut.
In Halo (1), Jenna reveals to Sav that Kyle can't make it with her to parental classes so Sav offers to go with her.
In LoveGame, Jenna arrives at Kyle's apartment and he rants about how K.C. isn't doing his half of the parenting work. Jenna argues with him and asks him if he can stay, but he leaves for work.