The campaign is expected to focus on issues of affordability, the economy and climate issues.
All have been campaigning unofficially for weeks, making early policy promises while also trying to hit their rivals where it hurts, whether the broken promises of the Liberals or controversial positions held by Conservative Leader Andrew Scheer.
"My job as prime minister is to be there to stand up for and defend Canadians' jobs", he said.
He says that the election is a chance for Canadians to vote for the kind of Canada they want to live in.
Trudeau began his first remarks of the campaign by recalling the victims of the September 11, 2001 terrorist attacks on the United States.
The worst hit to Trudeau's progressive image came with the SNC-Lavalin inquiry, a corruption scandal in which Trudeau was accused of interfering in the criminal prosecution of a Quebec-based engineering firm.
Asked what his government is hiding, Trudeau says his office gave the largest waiver of cabinet confidences in Canadian history but added anything more. Trudeau will set the process in motion to dissolve Parliament by meeting with Governor General Julie Payette at Rideau Hall.
Canada's prime minister will officially announce the start of the federal election campaign this week.
The NDP are polling nationally in third place, on roughly 13%-14% support, with a slight lead over the Green Party.
Climate change is also an important issue to voters, according to opinion polls.
"I've made my views of Bill 21 known", Scheer said in Ottawa Wednesday morning, before heading for his official campaign launch in Quebec.
"We've done a lot together these past four years, but the truth is we're just getting started", said Trudeau, moments after asking Governor General Julie Payette to dissolve Parliament and launch the campaign for the October 21 vote.
Scheer, the head of the conservative party, said today that Trudeau had lost the moral authority to govern.
Much of his attack arises from a report in the Globe and Mail that cabinet confidentiality is preventing people from speaking to the RCMP as the force considers a possible investigation into obstruction of justice.