Mr. Steele accepted the selection after a prolonged standing ovation from members who were clearly tired after five hours of voting.

“As a little boy growing up in this town, this is awesome,” he said.

Mr. Steele also signaled that after an election in which there were signs that the party was shrinking  in terms of parts of the country and groups it was appealing to  he would make a concerted effort to get the party back on track and compete with Democrats. His speech offered a sharp contrast of tone in a meeting that had been marked by expressions of concern by leaders of the party.

"It’s time for something completely different and we’re going to bring it to them," Mr. Steele said. "We’re going to bring this party to every corner, to every boardroom, to every neighborhood, to 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 be with us and for those of you who are going to obstruct, get ready to be knocked over.’ "

Mr. Steele was one of two African-Americans competing to be the party’s leader. The other was Ken Blackwell, the former Ohio secretary of state. Mr. Blackwell quit the race after the fourth ballot, in which he drew just 15 votes. He then endorsed Mr. Steele, which had ideological significance: Mr. Blackwell was among the most conservative candidates in the race, and there were recurring concerns among some conservatives about Mr. Steele’s convictions.

The results also signaled a desire by the party to make a clear break with former President George W. Bush. The incumbent chairman, Mike Duncan, who had been installed in the job by Mr. Bush, withdrew after the third ballot, in which he got just 41 votes, compared with 52 votes in the first ballot.