"It's time for something completely different and we’re going to bring it to them," Steele said.
Steele won after six ballots by a vote of 91 to 77, with 85 votes needed to win.
Steele, a Roman Catholic former corporate lawyer, has promised to close the digital divide with Democrats who have used the internet to raise record amounts of money and build an army of volunteers.
Some Republicans have accused Steele of being insufficiently conservative because of his past association with a moderate-leaning group.
Camille Elhassani, Al Jazeera's White House producer, said Steele faces an electorate that has not only abandoned the traditional Republican Party but is openly hostile to them, following eight years of George Bush, the former US president.
Elhassani said Steele would have to focus on uniting the Republicans with a new strategy and message.
Steele also acknowledged the historic nature of the vote and the need to take the party in a new direction.
"We're going to bring this party to every corner, every board room, every neighborhood, every community. And we're going to say to friend and foe alike, we want you to be a part of us, we want you to work with us."
His election could help counter a view that the party has exploited racial tensions to win white votes since the 1960s.