The move could help Mr. Obama avoid a potentially nasty election-year nomination fight with Republicans, largely because Ms. Kagan lacks a judicial record that could be parsed for controversial rulings and opinions.
Not since 1972 has a Supreme Court justice been seated on the bench without having prior experience as a judge - all eight current justices have served on the U.S. federal appeals court.
Mr. Obama described Ms. Kagan as "one of the nation's foremost legal minds" and stressed her record of seeking a diversity of conservative and liberal views as dean at Harvard. "She believes, as I do, that exposure to a broad array of perspectives is the foundation . . . for a successful life in law," Mr. Obama said.
If confirmed, Ms. Kagan would become the third woman on the current Supreme Court and only the fourth in history. She would join Justices Ruth Bader Ginsburg and Sonia Sotomayor, who Mr. Obama selected last year as his first high court nominee. Ms. Kagan has been considered the frontrunner to win the nomination almost from the moment 89-year-old Justice John Paul Stevens retired last month.
At the time, Mr. Obama said he wanted a Supreme Court nominee who had "a keen understanding of how the law affects the daily lives of the American people" - a quality he sought last year in picking Sotomayor to be the first Hispanic-American high court justice.