The announcement comes just 11 days shy of his 90th birthday. Read Stevens' retirement letter, which was sent to Pres. Obama.
He had indicated two years ago he was ready to retire, but wanted go step down when a liberal progressive was in the White House to nominate his replacement. After Pres. Obama's election, it was only a matter of time.
So it was no surprise to Northwestern University professor and former law school dean Robert Bennett to hear Justice Stevens' announcement. Bennett has known Stevens, who at 89 is the oldest member on the Supreme Court, for 30 years.
"He had an idea of what a justice should be and he was true to it. And it's an interesting vision of what a justice should be- independent, really your own decision maker," said Professor Robert Bennett.
Stevens graduated high school from the University Of Chicago Lab School and earned a bachelor's degree in English from the University of Chicago in 1941. His Hyde Park beginnings are familiar to President Obama who praised the justice who sat on the nation's highest court for nearly 35 years.
"During that tenure he has stood as in impartial guardian of the law. He has worn the judicial robe with honor and humility," said President Barack Obama.
When Stevens was appointed by President Gerald Ford in 1975 he was considered a moderate conservative. Legal experts now consider Stevens a leader on the court's liberal wing.
"Stevens, I think came to see that over time that religious minorities, racial minorities, persons accused of crime, political dissidents are the kinds of individuals who most need the protection of the court," said Prof. Geoffrey Stone, University of Chicago Law School.
U.S. Solicitor General Elena Kagan, a former U of C professor, Federal Appeals Court Judge Merrick Garland, who grew up in Lincolnwood, and Appellate Judge Diane Wood of Chicago are considered by legal experts to be among the contenders to replace Stevens.
"The President needs to make an appoint relatively soon and hope that the person will be confirmed before the court sits again come early October," said Professor Harold Krent, Kent College of Law.
The president's nomination of a successor will follow the heated Washington battle over healthcare. Stevens wants his replacement named and confirmed by October-- before the November election.
"He's not going to want to pick a fight with the Senate so I think he'll look for someone who is imminently confirmable," said Geoffrey Stone.
The president is expected to act quickly in naming his choice to replace Stevens. Kagan and Judge Wood were both vetted during the process that nominated Judge Sonia Sotomayor. So some of the White House work is already done.
Stevens retirement will not change the conservative-liberal split
Chief Justice John Roberts said in a written statement that Stevens "has enriched the lives of everyone at the Court through his intellect, independence, and warm grace."
Senate confirmations of Supreme Court justices have increasingly become political battles and this one will come amid the added heat of congressional election campaigns.
Sen. Patrick Leahy, D-Vt., chairman of the Senate Judiciary Committee, appealed for civility. "I hope that senators on both sides of the aisle will make this process a thoughtful and civil discourse," Leahy said.
Looking toward those hearings, Senate Republican Leader Mitch McConnell of Kentucky said, "Americans can expect Senate Republicans to make a sustained and vigorous case for judicial restraint and the fundamental importance of an evenhanded reading of the law."
Stevens informed Obama in a one-paragraph letter addressed to "My dear Mr. President." It was delivered to the White House by court messenger at 10:30 a.m. EDT, two minutes before the court's public announcement. The news came on a day when the court wasn't in session.
White House counsel Bob Bauer telephoned the news to Obama on Air Force One, as he returned from a trip to Prague.
The leading candidates to replace Stevens are Solicitor General Elena Kagan, 49, and federal appellate Judges Merrick Garland, 57, in Washington and Diane Wood, 59, in Chicago.
Stevens' departure will not change the court's conservative-liberal split because Obama is certain to name a liberal-leaning replacement, as he did with his first nominee, Justice Sonia Sotomayor. But the new justice is not likely to be able to match Stevens' ability to marshal narrow majorities in big cases.
Stevens was able to draw the support of the court's swing votes, now-retired Justice Sandra Day O'Connor and Justice Anthony Kennedy, to rein in or block some Bush administration policies, including the detention of suspected terrorists following the Sept. 11, 2001, attacks, its tilt toward protecting businesses from some lawsuits and its refusal to act against global warming.
But after the arrival of Roberts and Justice Samuel Alito, President George W. Bush's appointees, Stevens more often was among the four liberal justices in dissent.
Stevens' recent dissent in a major case involving campaign finance laws showed both the eloquence of his writing and, in his stumbling reading of his opinion in the courtroom, signs that his age might at long last be affecting him, though he remains an active tennis player and swimmer.
Stevens known as the court's prolific, lucid writer
He is the court's last World War II veteran and that experience sometimes finds its way into his writings, recently in a reference to Tokyo Rose, the English-speaking Japanese radio announcer who addressed U.S. soldiers in the Pacific.
Stevens had a reputation as a bright and independent federal appeals court judge when Ford, acting on a recommendation by Attorney General Edward Levi, nominated him to the Supreme Court.
His friendly manner of questioning lawyers who appeared before the court could not hide Stevens' keen mind. His questions often zero in on the most telling weaknesses of a lawyer's argument and the case's practical effect on everyday people.
A pleasant, unassuming man, Stevens has been a prolific and lucid writer. For many years, he wrote more opinions each court term than any other justice.
Most justices let their law clerks write the first drafts of opinions, but Stevens has used his clerks as editors.
He'd write the first draft and submit it to the clerks for comment. "That's when the real fun begins," Stevens once told a visitor. "The give and take can get pretty fierce."
As a result, his opinions have reflected his personal writing style -- a conversational one that contrasted sharply with the dry, dull efforts of some other justices.
He had said that one sign of his time to retire would be an inability to churn out those first drafts. But he insisted in recent days that he was still writing them.
A member of a prominent and wealthy Chicago family, Stevens spoke proudly of being a Cubs fan who was at Wrigley Field for the 1932 World Series game when Babe Ruth supposedly pointed to the spot where he would hit a home run. He met many celebrities of the day when they stayed at his family's hotel in Chicago, including aviation pioneer Amelia Earhart.
Stevens graduated from the University of Chicago. After serving in the Navy during World War II, he earned a law degree from Northwestern University, finishing first in his class. He later taught antitrust law at both schools.
In 1979, Stevens became only the second justice to divorce while serving on the court. Stevens and his first wife, Elizabeth Jane Sheeren, had four children. He later married a former Chicago neighbor, Maryan Mulholland Simon.
An avid bridge and tennis player, Stevens also is a licensed pilot. From autumn through spring, he and his wife routinely travel to his condominium in Fort Lauderdale, Fla.
"I lead an average life, just like anybody else," Stevens once told an acquaintance. "I play bridge, play tennis, try to play better golf. I'm very comfortable here."
Even in his late 80s, Stevens said he swam every day and continued playing tennis several times a week. He described reading legal briefs on the beach, noting his colleagues' jealousy when in court one day he opened a brief and grains of sand spilled out.
The Associated Press contributed to this report. All rights reserved.