How had Tom Robinson been in trouble with the law before To Kill a Mockingbird?
Tom has been in trouble with the law, but it was a misdemeanor charge, as we learn during his cross-examination. In fact, it's the first question Mr. Gilmer asks him.
"You were given thirty days once for disorderly conduct, Robinson?" asked Mr. Gilmer.
Tom goes on to say that he was in a fight with another black man. Tom also reveals that he was the one beaten in the fight. Mr. Gilmer doesn't want to hear that however; he has other interests.
"Yes, but you were convicted, weren't you?"
Atticus raised his head. "It was a misdemeanor and it's in the record, Judge." I thought he sounded tired.
"Witness'll answer, though," said Judge Taylor, just as wearily.
"Yes suh, I got thirty days."
Both Atticus and Judge Taylor can see that Mr Gilmer is simply trying to prejudice the jury against Tom, and it makes them suddenly tired of fighting the inherent racism of the town. Yet they cannot stand completely against it, & Tom is forced to admit that although it wasn't his fault, he was convicted of a misdemeanor charge.
Tom Robinson has only been in trouble with the law once previously before he is accused of raping Mayella Ewell in Harper Lee's novel, To Kill a Mockingbird. A twenty-five year old married man, Tom spent 30 days in jail after being found guilty of a misdemeanor count of disorderly conduct after getting in a fight with a man armed with a knife. He was cut--"a little, not enough to hurt"--on his disabled left arm. Both men were charged; the assailant paid his fine, but Tom served the time since "I couldn't pay the fine." Despite a staunch defense by Atticus Finch, Tom is found guilty of the capital crime.
Tom in the book To Kill a Mockingbird is the black man accused of raping a young white girl, Mayella Ewell. Tom is quiet and respectful. He stands trial and Atticus a local lawyer defends him. Tom is an easy target to be accused by the girl and her father. He gets setup by them after her father rapes and beats her. In the book we learn that Tom had a record for a previous arrest for disorderly conduct. He is a poor black man, fairly innocent and unable to defend himself against an all white jury that has pretty much already made up their mind. The book is a story of racism at its worst and of the few people who stand up against it because they follow their own moral beliefs and not what others expect from them.
Tom was only in trouble one time previously before being wrongly accused of raping Mayella. This occurred when he was in a fight with a man and he was only slightly cut within this process. Because Tom could not pay, he had to serve his time in jail.