The former New York appeals court judge was confirmed in 2009 by the Senate in a 68-31 vote, making her the 111th justice.
"With this historic vote, the Senate has affirmed that Judge Sotomayor has the intellect, the temperament, the history, the integrity and the independence of mind to ably serve on our nation's highest court," President Barack Obama said of her confirmation.
Sotomayor replaced retiring Justice David Souter, a nominee of President George H. W. Bush and one of the court's most reliably liberal votes.
Sotomayor was born June 25, 1954, in the Bronx. Born to a Puerto Rican family, Sotomayor grew up in a public housing project in New York's South Bronx neighborhood. Her father died when she was nine and her mother is credited with working six days a week to send Sotomayor and her brother to school. In addition to the challenges facing the young Sotomayor, she was diagnosed with diabetes when she was eight years old.
She went on to graduate from Princeton University in 1976 and received her law degree from Yale in 1979, where she was the editor of the Yale Law Journal. She worked as assistant district attorney in New York for five years before going into a private practice in 1984.
By the early 1990's, she had attracted the attention of political leaders and in 1992, with the support of New York Sen. Daniel Patrick Moynihan, she was appointed by President George H. W. Bush to be a federal judge for the Southern District of New York.
In 1997, President Bill Clinton named her judge on the 2nd U.S. Circuit Court of Appeals in New York. Senate Republicans delayed her confirmation because of the possibility of her becoming a Supreme Court nominee but she was eventually confirmed in 1998 with a 68-28 vote.
She authored more than 150 decisions in the 2nd Circuit, and two of those were overturned. A third was under review as of May 2009.
During her confirmation process, one of her decisions on the 2nd Circuit garnered particular attention when it was appealed to the U.S. Supreme Court. The decision involved a group of white firefighters in New Haven, Conn., who said they were passed over for a promotion when the city declined to implement the results of a performance test in which minority firefighters scored badly. Sotomayor was part of a judicial panel that denied the firefighters' claims and supported the city of New Haven.
Upon appeal, the Supreme Court ruled in June 2009 that the white firefighters were unfairly denied promotions due to their race, reversing the lower court decision Sotomayor had backed as an appeals judge.
During her confirmation process, 57 of 58 Democrats voted in favor of Sotomayor, as did two independents. Only an ailing Sen. Ted Kennedy, D- Mass., missed the vote. He remained in Massachusetts suffering from brain cancer.
Though Democrats touted Sotomayor as a mainstream moderate, some Republican senators argued that she would bring personal bias and a liberal agenda to the nation's highest court.
"Unfortunately, Judge Sotomayor's speeches and writings over the years reveal a judicial philosophy that highlights the importance of personal preferences and beliefs in her judicial method," said Sen. Charles Grassley, R-Iowa.
Some GOP opposition to the nominee centered on concerns over past speeches, especially her use of the phrase "wise Latina" in a 2001 speech. During the remarks, Sotomayor told Hispanic law students she hoped: "a wise Latina woman with the richness of her experiences would more often than not reach a better conclusion than a white male who hasn't lived that life."
During her confirmation hearings on Capitol Hill, Sotomayor sought to explain the controversial remarks: "No words I have ever spoken or written have received so much attention," she said on July 14, 2009.
"As my speech made clear, in one of the quotes that you referenced, I was trying to inspire them to believe that their life experiences would enrich the legal system, because different life experiences and backgrounds always do. I don't think that there is a quarrel with that in our society."
Some Latino politicians warned that demonizing Sotomayor because of the remarks would have political repercussions.
"To say you cannot vote for this qualified Latina sends a message to us, as a community, that we will not forget," said Sen. Robert Menendez, D-N.J., according to the Washington Post.
Nine Republicans ultimately reached across the aisle and voted for Sotomayor. Ohio GOP Sen. George Voinovich, for example, rejected the idea that Sotomayor's record aggressively leaned left.
"Judge Sotomayor's opinions for the most part were lengthy, workmanlike, limited rulings, the sort of opinions that exhibit the judicial restraint one would hope for a Supreme Court justice," he said.