WASHINGTON — President Obama on Monday plans to nominate Anthony R. Foxx, the mayor of Charlotte, N.C., to be the next secretary of transportation, choosing a rising young African-American from the South to balance out a cabinet criticized for a lack of diversity.

Mr. Obama also appeared close to nominating Penny Pritzker, a hotel magnate, longtime friend and fund-raiser, as the next commerce secretary, and Michael Froman, his international economics adviser, as the United States trade representative, although neither nomination was scheduled to be announced on Monday.

The selections, all of which would require Senate confirmation, would help fill out Mr. Obama’s second-term cabinet more than five months after his re-election. Consumed by fiscal clashes and legislative battles and delayed by painstaking vetting, Mr. Obama has been slow to finish assembling a team to carry him through the second half of his administration.

Word of Mr. Foxx’s nomination, confirmed on Sunday by White House officials who insisted on anonymity to discuss it before the formal announcement, comes at a time when the president has been scrutinized for the demographic makeup of his circle. After drawing criticism that many of his initial second-term national security picks were men, Mr. Obama has named a succession of women and minorities to other top-level posts.