US President George Bush has nominated federal appeals court judge John Roberts to fill the vacancy on the Supreme Court.
Judge Roberts is a conservative on social issues
President Bush said Mr Roberts had "superb credentials and the highest integrity" for the powerful post.
Mr Roberts, 50, was appointed to the appeals court two years ago, and also served under George Bush senior.
A staunch conservative, he is likely to face tough confirmation hearings in the Senate over issues such as abortion.
If confirmed, Mr Roberts will be the first new judge to join the Supreme Court for 11 years, and could help shape decisions on controversial issues like abortion for decades.
Speaking at the White House with Mr Roberts by his side, Mr Bush said the judge possessed "one of the best legal minds of his generation".
"He has the qualities Americans expect in a judge," the president said. "Experience, wisdom, fairness and civility."
He said Mr Roberts had a profound respect for the rule of law and would not "legislate from the bench".
The nine-seat Supreme Court is one of the most important institutions in the US, with an influence on politically and socially volatile issues like abortion.
The vacancy was created by the retirement of Judge Sandra Day O'Connor earlier this month.
Justices are named for life, and experts say Mr Bush's nomination gives him the chance to expand his conservative agenda and extend it well past his presidency.
The BBC's James Coomarasamy, in Washington, says conservatives will be pleased by Mr Roberts' record on abortion, church-state issues and the environment.
Mr Roberts has successfully argued before the Supreme Court that government-funded doctors and clinics could not talk to patients about abortion.
Announcing his choice, Mr Bush said he was confident of a "timely" confirmation, adding that he wanted Mr Roberts in place before the Supreme Court reconvenes in October.
The confirmation hearings are expected to start at the end of August.
Mr Roberts had been considered one of the less contentious candidates for the hugely powerful and politically sensitive post, our correspondent says.
Justice O'Connor announced her retirement earlier this month
A Harvard graduate from Buffalo, Mr Roberts was a former clerk to Chief Justice William Rehnquist and worked in the justice department during the Reagan presidency.
He was a deputy solicitor general under George Bush senior before becoming a private lawyer.
He went on to join the US Circuit Court of Appeals for the District of Columbia in May 2003 after being nominated by Mr Bush.
US legal experts had mentioned several women in the long list of possible successors to Justice O'Connor - and First Lady Laura Bush had said publicly that she hoped her husband would name another woman.
Justice O'Connor held a swing vote in the court, so her replacement will have an immediate influence on matters where the other members are divided, analysts say.