Justin Trudeau arrives at Rideau Hall with his family before being sworn in as the 23rd Prime Minister of Canada  in Ottawa on Wednesday. 

AFP/Ottawa

Justin Trudeau was sworn in as Canada's 23rd prime minister on Wednesday before a packed, flag-waving crowd, almost 50 years after his father took on the job.

The 43-year old former French teacher overcame campaign attack ads claiming he was "just not ready," winning the October 19 election by a landslide and bringing an end to nine years of Tory rule.

With his dark mop of curly hair, a confident swagger and hints of his father's speech, the younger Trudeau stood tall, smiled and mouthed "Thank you" as applause erupted after he took the oath in the ballroom of the governor general's mansion.

Aboriginal throat singing capped off the event, attended by aboriginal and military leaders, former prime ministers and past governors-general, and others.

Earlier, Trudeau's mother Margaret had been first to arrive for her son's swearing-in at Rideau Hall - the official residence of the governor general - carrying his youngest son Hadrian and with his two other children, Ella-Grace and Xavier, in tow.

Trudeau himself and his cabinet pulled up soon afterward in a bus, eschewing individual limousines traditionally used to ferry government ministers around the capital, and then walked up a winding lane to the governor's mansion.

His team includes some well-known personalities such as former astronaut Marc Garneau, former Liberal leader Stephane Dion, as well as several fresh faces.

Under a bright blue sky and colorful fall foliage, a large crowd gathered for the event, amid a carnival-like atmosphere.

For the first time ever, the Canadian public was officially invited to witness the swearing-in ceremony in person. Two massive screens were set up outside the mansion for additional public viewing.

Many people had travelled to Ottawa from Montreal and Toronto for the ceremony, and camped out to get a glimpse of the new prime minister, who glad-handed dozens of people as he walked in with his wife Sophie Gregoire and his inner circle.

Family ties  

The family is often compared to the Kennedys in the US.

Pierre Trudeau, who died in 2000, was prime minister from 1968 to 1979, and again from 1980 to 1984. He is considered the father of modern Canada.

At 43, Trudeau is the nation's second youngest prime minister after Joe Clark in 1979.

Trudeau was first elected to the House of Commons in 2008, after years trying out different roles. He worked as a whitewater guide, snowboard instructor, bartender, bouncer and public speaker.

After the ballroom ceremony, he was expected to deliver a statement and hold the new government's first cabinet meeting.

He and his family will not move into the prime minister's official residence at 24 Sussex, where Trudeau grew up, because it must undergo a massive renovation. Instead they will stay at a guest house on the governor general's estate.

Parliament, meanwhile, is expected to be recalled in December after Trudeau returns from four back-to-back international events including UN climate talks in Paris.