Groups of mostly Liberal supporters cheered and waved campaign signs at a couple of Trudeau's stops in a city long considered an NDP stronghold.
"I've had a long friendship with Stephen McNeil and he impresses me as an extraordinary leader," said Trudeau in between stops where he shook hands and posed for photos.
"I'm glad to help out Stephen bring the kind of change that Nova Scotia needs."
Trudeau's stops included ridings in Dartmouth and Spryfield. The Liberals are targeting some Halifax-area ridings where NDP incumbents aren't seeking re-election.
McNeil said he welcomed Trudeau's support, which comes just past the midway mark of the campaign, calling it a "shot in the arm."
"Nova Scotians are energized whenever he's around and certainly our base and workers are extremely energized when he's around," McNeil said.
"There's a huge support from Liberals when he's in town, but we see it spilling over to the undecided voters who are intrigued by his frankness and openness."
Trudeau's visit came as the Progressive Conservatives accused McNeil of defending "gold-plated" pensions for legislature members.
McNeil said his party is open to re-examining all aspects of remuneration for politicians.
"No elected member gets into this business for the salary or the pension," he said. "There's a term for them and it's a one-term MLA because they don't get re-elected."
McNeil also spent the day highlighting his platform promise to cap class sizes, but he added that the process would allow for schools to exceed the cap, though they would be required to have an educational assistant in the classroom.
He said the plan could see an additional 130 teachers and 130 educational assistants hired.
Elsewhere on the campaign trail, Premier Darrell Dexter announced that the NDP would open four new community health clinics in underserved areas of the province if his party is re-elected on Oct. 8.
Dexter said he would work with nurses, doctors and communities to determine where the clinics are needed most, adding that they would open over the next four years, with the first opening in 2016.
"Better care clinics will focus on providing more basic and chronic care to patients in the communities where they live," Dexter said in a statement.
A spokesman for the party said $2.4 million would be set aside to build the clinics.
Progressive Conservative Leader Jamie Baillie said his promise to scrap the pension plan for politicians would see a citizens panel struck to set the pay and benefits members receive. Baillie said the pension for politicians doesn't treat taxpayers fairly.