David MacNaughton, known for his work in Ontario's public and private sector, has been named Canada's new ambassador to the United States, taking over from former Manitoba premier Gary Doer.

Marc-André Blanchard will become the country's new ambassador to the United Nations in April, Foreign Affairs Minister Stéphane Dion said as he announced several diplomatic appointments on Saturday.

The others include:

  • Angela Bogdan, who joined External Affairs Canada in 1984, will become consul general of Canada in Sydney, Australia, effective immediately.
  • Marie-Louise Hannan, who has worked in the diplomatic services since 1997, will become ambassador to the Association of Southeast Asian Nations in Jakarta, Indonesia, effective immediately.
  • Susan Harper, who also has experience as a senior diplomat, joining External Affairs Canada in 1983, will become consul general of Canada in Miami, Fla., effective immediately.

A long-time political strategist, MacNaughton served as Ontario co-chair for the federal Liberal campaign that saw Justin Trudeau elected prime minister last October.

The newly named ambassador also has a long history behind the scenes of Ontario politics.

In 1987, he chaired former Liberal premier David Peterson's election campaign. He served as a senior advisor in the 2003 provincial election that saw Dalton McGuinty elected premier and then as his principal secretary from 2003-2005, which some have commented about on Twitter.

He more recently held the job of chairman and CEO of StrategyCorp, a communications and management consulting firm.

MacNaughton replaces Doer, who was NDP premier of Manitoba from 1999 until 2009. Doer confirmed in October 2015 he would be stepping down as U.S. ambassador after six years holding the position, a longer-than-normal tenure.

Canada's embassy in Washington, D.C., welcomed MacNaughton on Twitter Saturday morning.

Blanchard, who has several degrees, including a master's in international law from the University of Montréal, was named among the 25 most influential lawyers in Canada by Canadian Lawyer Magazine in 2013.

The chair and CEO of law firm McCarthy Tetrault said it was an "immense honour" to be appointed Canada's ambassador to the United Nations

"Being asked to lead Canada's mission to the United Nations is an immense honour, particularly at a time when Canada has re-committed itself to multilateral diplomacy and to engage more widely on the international scene," said Blanchard in a statement posted to the law firm's website.