Caroline Kennedy, the daughter of former President John F. Kennedy, is close to being announced as the next United States ambassador to Japan, according to people familiar with the appointment process.

The vetting of Ms. Kennedy by the White House is almost complete, and an appointment could be announced in the coming weeks, along with the names of several other choices for high-profile diplomatic posts.

Ms. Kennedy was an early supporter of President Obama, offering forceful backing as he battled Hillary Rodham Clinton for the Democratic nomination in the 2008 presidential election. She also served as a co-chairwoman of Mr. Obama’s 2012 re-election campaign.

Sending Ms. Kennedy to Japan would continue a long tradition by presidents of appointing high-profile people to that post. Those have included Walter F. Mondale, the former vice president; Mike Mansfield, the former Senate majority leader; and Tom Foley, the former speaker of the House.

From The New York Times