Good Question: Reply All: Ambassadors, Lottery Tickets & ‘Oh Boy!’Caroline Kennedy was sworn in as the ambassador to Japan on Tuesday. So, that had Wendy from Eagan wondering: What does being an ambassador entail? According to the U.S. State Department, a U.S. ambassador is the president’s highest-ranking representative to another country. That person’s main role is to coordinate the Foreign Service office and the staff that serves under him or her. An ambassador is nominated by the president, but must be approved by the Senate. Some ambassadors are long-time diplomats, and others have been political friends or allies. In this case, Caroline Kennedy is a well-known person from prominent political family who will fill a high-profile ambassadorship.