Well, even being the second son of Ma and Pa Joad, this character is the main one in the novel. We get acquainted with him at the beginning of the novel. Immediately we get to know that he has just released from the prison being there for 4 years. Maybe this was the reason why he is a little different and almost a stranger. When he came back home, he found out that his family has lost a farm and is now moving west to another state in California.
In this book, he is a plainspoken as his father, and also a forthright man. Also, he still retains some of his violent tendencies. Likewise, Tom shows the most growth in his realization of the concept of human unity and love. Tom is more a practical person; he thinks that it is more important what is here and now rather than what will be in the future. Who knows if that future will become?
He has strengths and weaknesses as any other character. His strong points are honesty, ability to see only the best in people and to give advice (really good ones, and not like chatterbox). For example, in one episode he tells the one-eyed mechanic (who cries about how lonely he is) to get an eye-patch and to take a bath (and probably this will increase his level of attraction). That's pretty practical advice.
When Noah tells Tom that he is going to leave the family, Tom tries to tell him it's a bad idea because the family is the most important thing. When his another brother Al feels very bad and sorry for breaking the touring car, he says that saying bad words on himself will not save a situation – he has to gather and repair. His biggest weak and bad point is that he killed a person, though we don’t know why he did it, and what the reason for such behavior is.
Tom Joad in the Essays