The case he took on involved a Georgia man called James Moseley, who was fighting a custody battle with his estranged wife.
In order to secure custody of the children, Moseley's wife accused him of sexual assault - rape and two counts of "aggravated" oral sodomy. The jury did not believe the wife, whose own sister testified against her, and found Moseley not guilty.
But Clayton County Superior Court Judge William Ison decided - having heard Mr Moseley claim that the oral sex with his wife had always been consensual - decided the defendant had to go to jail. Having been advised not to appeal by his first lawyer, Moseley was sentenced to five years. In the prison exercise yard, Moseley would rub shoulders with killers and armed robbers who laughed when he told them his crime. Soon he started telling people he was a killer.
In a memorable appeal, Mr Smith used Georgia's own laws to overturn the sentence - but not the conviction - and have Moseley freed. "Mr Moseley was eligible for 20 years for his heinous crime," it read. "Had he committed the same offence with his wife after she was dead, he could only have received half the time. Had he had intercourse in the courtroom during the trial, his punishment would still have been less. Indeed, had he chosen not his wife, but a donkey, he could only have received one-quarter of the sentence. Had he committed the crime with a deceased donkey in the public square, he could not have been sentenced to as long in prison as for having oral sex with his wife. The law is patently unconstitutional as applied to Mr Moseley in this case."