Tory backbencher John Bercow has won the race to become the 157th Commons Speaker, and is the first Jew to take the role.
He received 322 votes to his rival and fellow Conservative MP Sir George Young's 271.
The Buckingham MP was "dragged" to the chair when the result was announced, a tradition for a new Speaker. He then told MPs it was the "greatest honour" of his political life.
He will replace Michael Martin, who stepped down after nine years in the job amid the furore over MPs' expenses.
Mr Bercow pledged to cast aside his political views and be "completely impartial". He also congratulated his nine rivals.
"I thank you from the bottom of my heart for the confidence that you have placed in me," he said.
"My commitment to this House is to be completely impartial as between members of one political party and another. That is what it is about."
Mr Bercow, 46, finished first in all three rounds, winning the final poll with 322 votes to Sir George's 271.
In a packed chamber, the leaders of the three main parties welcomed his election. Gordon Brown, who declined to vote, said that it was an "important step" in the "process of change" following the expenses row.