In an event with as much prescribed formality as the installation of Louise Arbour as Governor-General, it was the tiny moments of humanity and individual expression that spoke most loudly of how she sees her role and the country she’s now serving in a new way.

Guests at the ceremony in the Senate on Monday morning included two former prime ministers, three former governors-general, multiple provincial lieutenant-governors, Supreme Court justices, several Order of Canada members wearing their medals, and one astronaut/new Canadian hero in the form of Jeremy Hansen.

Ms. Arbour is herself a former Supreme Court justice, who at different points in her illustrious career was also chief prosecutor for the International Criminal Tribunals on the former Yugoslavia and Rwanda, United Nations High Commissioner for Human Rights, and leader of an independent review on sexual misconduct and culture in the Department of National Defence and the Canadian Armed Forces.

She absorbed much of her installation ceremony with a quiet, delighted half-smile on her face.

There were moments when the stilted ritual of the day drew collective giggles from the assembled, imparting a sense that everyone there was doing something together. It happened when Defence Minister David McGuinty solemnly handed the new Governor-General the seal of Canada – a gleaming heft of silver and gold the size of a minor sports trophy – and she held it for one ceremonial moment before handing it right back to him.

Just before Ms. Arbour recited her oaths of office, an aide-de-camp in a military uniform stepped up with practiced efficiency to brandish an essential implement: the viceregal reading glasses, in a robin’s-egg blue case that screamed out its presence in a red-carpeted room full of dark suits. Again, a ripple of laughter rolled through the chamber.

Aside from official inclusions of O Canada and God Save the King, the musical selections for the ceremony were clearly meaningful.

When Sara Dufour performed a song by Quebec folk and rock band Les Cowboys Fringants, Ms. Arbour mouthed the words along with her. The song is called La Reine – “The Queen” – but it’s not about the Buckingham Palace sort that people in Ms. Arbour’s role represent in Canada. It’s about a woman everyone called the Queen, who looked after the struggling and the ignored in a rough part of Montreal: “At night, she made her rounds in her pickup truck / Handing out toast and some coffee / To give a little bit of warmth / To those who’ve got winter right in their hearts.”

Later, right before the speeches, singer-songwriter Tyler Shaw performed Like Me and You by Raffi Cavoukian – better known simply as Raffi to the Baby Beluga generation. Prime Minister Mark Carney and former prime minister Jean Chrétien, seated right behind him, both squinted up at video screens displaying lyrics about kids across the world, each one “a child of a mother and a father / A very special son or daughter / A lot like me and you.”

When it was finally Ms. Arbour’s turn to speak free of an official script, she offered a humble, reflective recitation of the life and career that led her to this point.