Based on his recorded feats, including lifting 500 pounds (227 kg) with one finger and backlifting 4,337 pounds (1,967 kg), former International Fitness and Bodybuilding Federation chairman Ben Weider stated in 2000, that Cyr is the strongest man ever.

From the age of twelve Cyr worked in a lumber camp during the winters and on the family's farm the rest of the year.

Cyr beat him in tests of lifting of heavy stones by hoisting a granite boulder weighing 480 lb (220 kg).

The fully grown male horse was placed on a platform with two iron bars attached, which enabled Cyr to obtain a better grip.

Soon proving his immense strength, he was urged by friends to enter the exciting, albeit highly precarious world of professional strong men, lifting mainly crude solid or shot-filled weights.

Prudent with his earnings, Louis left the police force and purchased a tavern/restaurant in St. Cunégonde, where he also featured a gymnasium that became a mecca for strength athletes and fighters.

Cyr's exploits had been well publicized in the 'Pink Un' or Police Gazette published by Richard K. Fox, the proprietor and promoter of other strength athletes, e.g. Travis, Eugen Sandow, etc.

Promoted by Fox, Louis went on tour circa 1885–1891 beating, amongst others: Sebastian Miller, Bienkowski, or Cyclops, August Johnson, and Richard Pennell, plus continually challenging, without success, Eugen Sandow, with a genuine diamond studded belt to be awarded to the winner, should such an event ever take place.

Sandow avoided any such challenges throughout his esteemed career after early mistakes, like the time he was beaten by McCann.

chest normal 59 1/2" and thighs 33" with other parts to match the increase in weight, being at the time a heavier 365 lbs.

[citation needed] While several of Cyr's feats of strength may have been exaggerated over the years, some were documented and remain impressive.

[citation needed] While in Ottawa he volunteered with the police when they took deputies to round up a local gang of miscreants; they turned him away claiming he would be too slow due to his bulk.

Statues of him are located at Place des Hommes-Forts and the Musée de la Civilisation in Quebec City.

John Grimek later also bent pressed it, half a dozen times or so one afternoon, when the weight was increased to 269.5 lb, by adding, as it happened, the lead type from Mark Berrys' classic tome Physical Training Simplified.

[citation needed] On 1 December 1891 at Sohmer Park in Montreal, before some 10,000 people, Cyr resisted the pull of four draught horses, two on each side, despite grooms cracking their whips to encourage the horses to pull harder and strain their haunches.

In January 1892, Cyr embarked in England with partner Horace Barré, arousing much interest and curiosity at his London debut at the Royal Aquarium, with 5,000 people packing the theater to watch Cyr's act and witness his open challenge to the wide world of strongmen, many celebrities of which were in the audience, with a side wager of £1,000 (Equivalent to about £98,070 as of 2015).

Many years later Doc Aumont, son-in-law of Louis, loaned Cyr's famous dumbbell to the Weider's Your Physique office in Montreal for a month, during which time over 500 people tried and failed to lift the weight.

Traveling extensively throughout the UK he also visited Scotland, raising and carrying for a distance one of the famed Dinnie Stones.

Cyr was very popular in Britain, being feted by celebrities and Royalty alike, including the Prince of Wales and Queen Victoria.

Cyr did a one-handed deadlift with a dumbbell weighing 525 lb (238 kg), made harder by the fact that the bar was 1.5 inches thick.

While in Montréal, Que., 25 March 1901, Louis Cyr wrestled Édouard Beaupré, who was known as a giant man.

Great homage was paid by all of Canada, with immense crowds attending the funeral and floral tributes coming from all over the world.

He was portrayed by Antoine Bertrand in the 2013 biographical film Louis Cyr, l'homme le plus fort du monde.