Hyeon Soo Lim, 60, was arrested in the capital Pyongyang after he travelled there in January for humanitarian work.
The Toronto-based pastor, who is of South Korean origin, was shown at a news conference earlier confessing to a plot to overthrow the government and set up a “religious state”.
North Korea bans religious activity.
The authorities periodically detain foreigners for religious or missionary activity and similar cases have seen staged public confessions from prisoners.
Canada’s foreign ministry said in a statement it was “dismayed at the unduly harsh sentence… particularly given his age and fragile health.” It added that Canadian officials were seeking access to Mr Lim.
Mr Lim was sentenced after a 90-minute trial at the North Korean Supreme Court.
He was convicted of joining the US and South Korea in an anti-North Korea human rights “racket” and fabricating and circulating false propaganda materials tarnishing the country’s image.
He was also accused of funding and helping “defectors” to escape, in some cases through Mongolia.
The pastor entered and left the court in handcuffs flanked by two public security officers in uniform, the Associated Press news agency reports.
Foreigners detained in North Korea
Recent cases (all American) include:
Matthew Todd Miller had been sentenced to six years’ hard labour in September 2014 for what North Korean state media described as “hostile acts”, but was released in November the same year
Kenneth Bae was arrested in November 2012 and accused of using his tourism business to form groups to overthrow the government. Sentenced to 15 years’ hard labour in May 2013 but released along with Mr Miller
Jeffrey Fowle, held for five months and charged with “anti-state” crimes -released in October 2014
Korean War veteran Merrill Newman held in October 2013 on charges of “hostile acts”, released in December the same year
The handcuffs were removed in court during the trial, it adds. The pastor kept his head bowed most of the time and answered questions in a subdued tone.
Mr Lim and his colleagues travelled to Pyongyang on 31 January as part of a humanitarian mission. His family said it was to support a nursing home, nursery and orphanage.
Mr Lim, who heads the Light Korean Presbyterian Church, had made numerous humanitarian aid missions to North Korea for nearly two decades, the Church said.
He was detained in February and in July a KCNA report said Mr Lim had given a press conference in Pyongyang where he admitted to using humanitarian work as a “guise” for “subversive plots and activities in a sinister bid to build a religious state”.
He also reportedly admitted to giving lectures that “North Korea should be collapsed with the love of ‘God’”, and to helping the US and South Korea to aid North Korean defectors.