One Big Happy Family is a live-action sitcom. The show consists of five seasons (four in production, as the second season has been split into two seasons).
- Sterling Knight as Dustin McKnight
- Brittany Curran as Penny McKnight
- Mike Weinberg as Tommy McKnight
- Jason Earles as Andrew McKnight (season 1-3)
- Michael Hitchcock as Fred McKnight (season 1-4; regular, 5; recurring)
- Sharon Jordan as Gracie McKnight
- Nicole Anderson as Nancy Carter
- Jennifer Tisdale as Elizabeth Pickett-McKnight (season 2-3)
- Daniel Samonas as David Brooks (season 1-2; recurring, season 3-5; regular)
- Bella Thorne as Lillian McKnight
The show is about a McKnight family. The family gets tired of living in a small town in Maryland, so they move to New York City. The show centers around the family who has to solve many problems, such as sibling disasters, relationships and friendships. The family has seven members. Fred and Gracie McKnight are the parents. The oldest child is Andrew McKnight, who has finished college and decided to stay with his family until he'll get married. First middle children are fraternal twins, Dustin (brother) and Penny (sister) McKnight, who are arguing a lot, but they need each other for some problems. The second middle child (three years younger than Dustin and Penny), Tommy McKnight, loves reading comic books and playing computer games. The youngest child is Lillian McKnight, who is very annoying and always has her doll, Baby, in her hands. Along for the family adventures, there is Penny's friend and neighbour, Nancy Carter, who can help the family. The McKnight family is the One Big Happy Family.