Step Brothers is about two grown men who live with their parents have to move in together because their parents got married. They are two men who are lazy. Off the bat, they don't like each other. They get into brawls in their front yard and the house. After they gang up on Derek, Brendan's mean little brother who is successful they realize they have a lot in common. They become best friends while their parents are thinking of getting them jobs so they can live on their own. They don't land jobs but they realize Brendan is a good singer and Dale is great on drums so they try to start a entertainment company but they destroy the parents boat while trying to start it up. Their parents can't handle them together so they get a divorce. The boys think it is their fault and they blame each other. They both try to keep getting them back together and at the end of the movie something special happens.

Will Ferrell is an actor and comedian who appears in comedy movies such as Semi-Pro, Talledaga Nights, Step Brothers, etc... Will Ferrell plays Brendan Huff in Step Brothers. He is portrayed the same as Johnn C. Reilly as a 39 year old stay at home son who was just recently laid off from his job at pet smart. He is a wild but very guy in the movie who sleep walks, licks dog turds, and doesn't know how to say Pam.

John C. Reilly is an American comedian and actor who plays in movies usually with Will Ferrell. They are know as the comedic duo with their movies such as Step Brothers and Talledaga Nights. John C. Reilly is portrayed in Step Brothers as Dale Doback. A lazy 39 year-old stay at home son who plays the drums. He says he wants to go into the family business but his dad is a doctor. In the movie he is very violent with almost killing Will Ferrell, burying him, and getting into a brawl with Will in front of their house with a baseball bat and a golf club.