A week after announcing his imminent resignation, Gov. Ricardo A. Rosselló of Puerto Rico nominated a new secretary of state who could succeed him. Pedro R. Pierluisi faces a confirmation hearing in the Legislative Assembly on Thursday.

But Mr. Pierluisi’s path to the governor’s seat is hardly an easy one. He faces serious opposition from some lawmakers, especially in Puerto Rico’s Senate, which could block his confirmation. That would leave the next in line — Wanda Vázquez, the secretary of justice — to become governor.

With the vote still uncertain, here is a look at the man who could take charge of the island’s troubled government.

Who is Pedro Pierluisi?

Mr. Pierluisi, a 60-year-old lawyer, served as secretary of justice for three years under Mr. Rosselló’s father, former Gov. Pedro J. Rosselló. He was elected to represent Puerto Rico in Congress as its nonvoting resident commissioner and served there from 2009 to 2017.