Johnny has the worst home life of any of the greasers. His father beats him all the time, and his mother pays little attention to him. So, the gang is his true family. He is the "gang's pet, everyone's kid brother." The smallest member and second youngest next to Ponyboy, Johnny was beaten badly when he was jumped by a gang of Socs. Since that time, he carries a knife, and he is always scared of being alone. However, he shows courage when he stands up to Dally at the drive-in in defense of Cherry, and the attention he receives from the girls is appreciated.
Later, he summons his courage again, using the knife when he sees Pony being drowned in the fountain, but it sickens him to know that he has killed "that boy." Even before the fire at the church, he realizes that they must go back and face the consequences, but he seems to understand that jail will be no worse than being with his parents. Johnny primarily wants to return for Pony's sake, since he knows Pony's brothers will be worried about his whereabouts and safety. When he realizes that it is their cigarettes which have caused the fire, Johnny is the first one into the church. As he explains later, the children's lives are more important than his own, and they owe it to the kids inside to get them out. As Johnny contemplates his future in the hospital, he is proud of his act of heroism. Knowing he is about to die, he writes Pony a last letter, telling him to never give up, and pressing him to try and convince Dally that he can still change his ways as well. Johnny really doesn't change that much over the course of the novel--he remains the down-to-earth kid that he always was--but circumstances create opportunities for him to step forward in truly heroic fashion, and he dies a tragic figure.