Cardinal Francis George says Pope Benedict XVI's decision to resign at the end of the month shows "great courage."
The 76-year-old cardinal is spiritual leader of the Archdiocese of Chicago, which serves more than 2 million Roman Catholics.
In a statement Monday, George says the pope has always "placed the will of God for the good of the Church before every other consideration."
George may play a role in electing the next pope since all cardinals under age 80 are allowed to vote in a secret meeting held at the Sistine Chapel.
The bishop of Joliet also issued a statement Monday. Bishop R. Daniel Conlon says the pope's announcement "comes as a surprise to all of us," yet is consistent with the pope's "humble disposition."