Angelu de Leon as Ma. Patrice "Peachy" Real-Torres nee da Silva – A main character from TGIS and Growing Up, Peachy was originally slated to get married to Wacks during the initial season of Growing Up, but eventually bailed. By the time of the events of Teen Gen, Peachy is a widowed single mother.
Bobby Andrews as Joaquin "Wacks" Torres III - The second of two main characters returning from TGIS and Growing Up, Wacks is Lucho's father and a motorcycle businessman. In the interlude between Growing Up and Teen Gen, Wacks is revealed to have gotten married and had a son, but the marriage fell apart because of irreconcilable differences. As a result, Wacks is committed to being a single father and aims to raise him as a responsible man. His world turns upside down just after moving into the subdivision only to discover that his old flame Peachy, was living next door, prompting him to confront her over their failed wedding.
Dianne Hernandez as Ma. Lyca da Silva – Peachy's only child, Lyca is a smart student at West Ridge High, running the school paper and often carries a camera. Her status makes everybody on campus think of her as a geeky outcast. She becomes the catalyst for Lucho's change of heart.
Juancho Trivino as Luis Joaquin "Lucho" Torres IV – Lucho is Wacks' only son and Team Gwapo's leader. Often seen as the bad boy, it is revealed that his rebellious behavior is because of resentment over his father's lack of time for him. His and TG's picking on Lyca gradually changes him into a more responsible person and likes her back. When his mother, Violet, warns that Peachy and Wacks' marriage will shoot down his chances of a relationship with Lyka, he dismisses it and resolves to take care of them.
Jeric Gonzales as Santiago "Tiago" Torres – Wacks' nephew and Lucho's cousin, Tiago is TG's resident musician. He is depicted as the son of a shipping magnate, but does not let his rich-kid status go to his head. Wacks often calls on him to rein in Lucho's bad behavior.
Thea Tolentino as Angela "Angge" Parahinog - Lyca's bestfriend in school, Angge comes from a poor family and being a breadwinner, often has to sell various food items on campus to raise money for her family and a future trip to South Korea. The latter is depicted as the ultimate achievement of her fascination with Hallyu culture. This causes her to frequently allude certain events to scenes in Korean drama series such as Endless Love and Boys Over Flowers. Although Angge is struggling to make ends meet, a dead aunt's family inheritance helps her family rise out of poverty.
Abel Estanislao as Jose Vicente "JV" Cortez - One of the four TG boys, JV is a young man from the province. He often has a penchant for romantic gestures.
Sunyee Maluche as Andrea "Drew" Remulla – The captain of the West Ridge High women's basketball team, Drew is JV's childhood friend. Often teased by Itos because of her seemingly tough exterior, Drew is actually very sensitive and romantic. Over the course of the series, Drew pines for affection from JV, who only sees her as one of the guys.
Gianna Revilla as Madison Avenida – One of the more popular girls in school, Madison is every bit a trendsetter and claims to have followers on Twitter and Instagram. She is one of the campus A-listers, but gradually hangs out with the other female characters.
Seth Patrick Isay as Carlitos "Itos" Buenavidez Jr. – Lucho's bestfriend and one of the four TG boys, Itos is the athletic type and tries to have his way with women. Isay left the show in late 2012, citing personal reasons. His character was written off as having signed up for a soccer league in the US.
Mikoy Morales as Xavier "Xavi" de Leon - Itos' "replacement" in the TG quartet, Xavi is depicted as a suave, debonair young man. He was dumped from the clique years before because of differences with the other members (especially Lucho), but they patch things up. Over the course of the show, he gradually works with Madison to try getting JV and Drew together.
