Kagan has never argued a Supreme Court case, but that will change as soon as next month, when the court takes up a dispute over the continuing viability of a key provision of the federal law that enforces the voting rights of minorities.
The case is perhaps the most important in the court's term and the Obama administration is mounting a vigorous defense of the landmark Voting Rights Act and its requirement that all or parts of 16 states with a history of discrimination get approval before instituting any changes that affect voting.
The government has not yet said who will argue the case, but the Solicitor General, the administration's top Supreme Court lawyer, typically handles the biggest cases.
David Garrow, a Cambridge University historian who has written about the court, said Kagan's first argument will be closely watched "simply because she's never given an argument before. But I don't think there's any chance for a train wreck. She's a smart person."
And she is no stranger to the high court. Kagan clerked for the late-Supreme Court Justice Thurgood Marshall and, in her role as dean of Harvard Law School, she has hosted several justices at events on campus. Among the school's alumni are Justices Stephen Breyer, Anthony Kennedy, Antonin Scalia, Souter and Roberts. A sixth justice, Ginsburg, began her legal studies at Harvard, but received her degree from Columbia University.
Kagan's efforts to bridge the divide between conservatives and liberals on Harvard's notably fractious faculty won her praise across the political spectrum. Several predecessors as Solicitor General, Republicans and Democrats alike, endorsed her nomination.
She and Roberts, both former Supreme Court law clerks, also share an odd history. Roberts was nominated for a seat on the federal appeals court in Washington in 1992, but not confirmed by a Democratic-controlled Senate. Kagan was nominated to the same court in 1999, but the Republicans who controlled the Senate then did not act on the nomination.
When George W. Bush became president in 2001, he nominated Roberts to the same seat Kagan had been chosen to fill. Roberts' nomination was held up by Senate Democrats for two more years before he was confirmed under the new Republican majority in 2003. He joined the high court two years later.
Kagan had little trouble winning confirmation as solicitor general, though only seven Republicans backed her. The 61-31 vote was seen as a warning to Obama that Senate Republicans "are not going to roll over" despite the hefty Democratic majority in Congress and Obama's solid win last year, said Curt Levey, executive director of the conservative Committee for Justice.