How does a president get impeached?
Impeachment is essentially the equivalent of an indictment in criminal court. This requires a simple majority of the House of Representatives. This does not mean that the president is removed from office, and if the House votes to impeach a president, they would go the Senate, where the Senate would vote to remove him/her.
How does a president get removed from office?
If 2/3 of the senate votes to convict the president, he would be removed from office. The chief justice of the Supreme Court presides over the hearing.
He violated the Tenure of Office Act, which said the president couldn't fire certain executive employees without Senate's approval, by firing Edwin Stanton, the Secretary of War. He was one vote away from being removed from office, with Edmund Ross, a Senator from Kansas, voting to keep him in office.
After the Monica Lewinsky Scandal, he was impeached on two charges- one of perjury, and one of obstruction of justice. The Senate didn't get enough votes to convict him.