Monday might be the last St. Patrick's Day that Mark Carney can truly claim to be Irish, as Canada's newly sworn-in prime minister moves to renounce both his Irish and U.K. citizenships.

Ex-central banker Mark Carney was sworn in as prime minister of Canada on Friday and immediately said he could work with U.S.

Mark Carney is a newcomer to elected politics, with decades of experience in finance. After his landslide victory, he pledged ...