The “Great Comet” is getting a new star.

Okieriete Onaodowan, who played Hercules Mulligan and James Madison in the original Broadway cast of “Hamilton,” will succeed the pop singer Josh Groban as Pierre this summer in the musical “Natasha, Pierre & the Great Comet of 1812.”

The casting choice is striking. It reflects a bet by Broadway that “Hamilton” alumni have ongoing, bankable box-office appeal (another member of the original “Hamilton” cast, Phillipa Soo, will star in an adaptation of “Amélie” opening in April). And it is the rare instance in which two black actors are leading the cast of a show that is not about black characters: Mr. Onaodowan will star opposite Denée Benton as Natasha.

Mr. Onaodowan, a son of Nigerian immigrants who was raised in New Jersey and took up acting when an injury ended his high school football career, will assume the role on July 3, the day after Mr. Groban’s departure, and has committed to staying until Sept. 4. The musical, set in 19th-century Russia, is adapted from a section of “War and Peace” in which Pierre is a wealthy but dejected member of the Moscow elite.