The governor general spent the holidays visiting Canadian soldiers and civilians in Italy and Afghanistan.
"The sacrifice of troops and civilians who are away from their families and friends at this time of the year is tremendous and I wish them the best of luck in the completion of their missions," David Johnston said in a statement.
He was joined on the trip by Defence Minister Peter MacKay, General Walt Natynczyk, chief of the defence staff.
Johnston had already been overseas for the state funeral of former Czech president Vaclav Havel, who died earlier this month.
Prior to the funeral, he, MacKay and Natynczyk visited with Canadian military personnel in Italy.
The approximately 250 sailors and air crew of the HMCS Vancouver joined a NATO counter-terrorism effort in the Mediterranean in November, after being deployed as part of the international mission in Libya.
Afterwards, the three men travelled to Afghanistan to celebrate Christmas with Canadians now stationed in Kabul.
The governor general met with Afghan President Hamid Karzai and other senior Afghan officials to discuss Canada's contribution to Afghanistan, while MacKay met with US General John Allen, who is commanding the international military presence there.
"Canadian Forces members have worked tirelessly, at home and abroad, to save lives, provide security, and promote peace," MacKay said in a statement.
"It has been a busy, challenging year. As we celebrate the holidays, we should also take time to think of those who are still deployed throughout the world."
Liberal Leader Bob Rae also joined the trip to Kabul, having asked the Conservatives in November if he could visit the troops over the holidays.
They agreed, provided he pay his own way to join up with the official delegation leaving from Kuwait City.
On Christmas Day, Johnston, MacKay, Natynczyk and Rae donned red and white Santa hats and led by the governor general, sang "We Wish You a Merry Christmas" with the soldiers, Rae said in a blog post about the trip.
Canadians are carrying out their duties with the utmost professionalism and distinction, Rae said in a statement.
"Especially during the holiday season, we recognize and appreciate their continued hard work and sacrifice as they celebrate away from their loved ones," he said.
"All Canadians should be proud of the work they are doing, as we continue our efforts to bring peace, stability and hope to a troubled region of the world."
The trip to Afghanistan had become an annual Christmas ritual for MacKay and Canada's top soldiers, who in past years spent the time at the base in Kandahar that used to be home to over 2,500 Canadian troops.
This year, around 950 soldiers are stationed in and around Kabul, providing classroom instruction to Afghan soldiers and police and trainers and also mentoring Afghan medical staff.
The training mission in Afghanistan, announced last year by the Harper government, got underway this past summer. Troops have arrived in the area in waves and serve an average of eight months in theatre.
Thus far, only one soldier has been killed as part of the mission, which the government initially described as "low risk."
Master Cpl. Byron Greff of the 3rd Battalion Princess Patricia's Canadian Light Infantry was killed when the vehicle he was riding in was struck by a powerful suicide car bomber on Oct. 29.