He was president of Iraq from 1979 to 2003.
He tortured and killed lots of his enemies and persecuted some ethnic groups.
He also used chemical weapons and started wars against two other countries in the region - Kuwait and Iran.
Many Iraqis wanted to see the end of Saddam Hussein's rule which is why there were scenes of joy when Saddam's statues were torn down during the war and when he was captured.
But he did have a strong inner circle of support through family and tribal links - and he was protected by fiercely loyal soldiers called the Republican Guard.
After Saddam Hussein's government fell, US forces spent months looking for him. They offered a reward of £15m for anyone who could tell them where he was.
In December 2003, they tracked him down to a small village and in an operation involving 600 soldiers were able to capture him alive.
He was found hiding in a tiny cellar at a farmhouse, about 15km (10 miles) south of his hometown, Tikrit.
Saddam Hussein during his presidency
Saddam was put on trial for murder, after being charged with being involved with the killing of 148 people in the village of Dujail in 1988.
The trial started in October 2004 but it did not go smoothly - two judges quit the case because of political pressure. Another quit for different reasons.
Two defence lawyers were killed and another fled the country.
Saddam was very argumentative when in the specially-built courtroom, and often said he didn't accept that the court was allowed to try him.
Saddam was sentenced to death on 5 November 2006. He appealed against the decision but he lost the appeal.
Saddam Hussein was killed by hanging on 30 December, 2006, in the Iraqi capital Baghdad.