Commander John Kenneth Leveson "Jack" Ross, CBE (31 March 1876 – 25 July 1951) was a Canadian businessman, sportsman, thoroughbred racehorse owner/breeder, and philanthropist.

In 1911, he set the world record for catching the largest tuna (680 lb; 308 kg) by rod and line at St. Anns, Nova Scotia.

Known as "Jack" to his friends, Ross grew up in Montreal's Golden Square Mile at his parents' French château-style mansion at 3644 Peel Street, designed by architect Bruce Price.

In co-operation with prominent Montreal businessman Sir Herbert Holt and others, Ross established Côte St. Luc Realties in 1911, which built the town of Hampstead, Quebec.

[3] After his father's death in 1913 (when he inherited $16 million), he moved back to his childhood home and used the second one to house guests, the newer one being too small for parties.

As a result, Ross built a summer home at St. Anns Bay in the northern part of Victoria County, Nova Scotia, on Cape Breton Island.

He had remarkable tenacity, bearing in mind that harnesses were not yet invented, on one occasion he fought a tuna for 19 hours before being forced to cut his line.

[4] On 28 August 1911, after a struggle of a mere four hours and forty five minutes, Ross landed a 680-pound (308 kg) tuna which set a record for the largest fish caught with a rod and reel.

He donated money to fund a new building (Ross Boarding House) at his alma mater, Bishop's College School, Lennoxville, and also gave liberally to McGill University.

The following year, Sir Barton set a world record for 1 3/16 miles on dirt in winning the 28 August 1920, Merchants and Citizens Handicap at the Saratoga Race Course.

However, plagued by tender hooves, Sir Barton was beaten in a now-famous match race on the hard dirt surface of Kenilworth Park in Windsor, Ontario by Man o' War.

In 1920, he had been appointed president of Blue Bonnets Raceway in Montreal, and although no longer a stable owner after 1928, he held the position until 1931, when he retired to a home in Jamaica.

Ross was widely respected for his good manners and sportsmanship, and the Canadian Horse Racing Hall of Fame says that the United States press called him "the best sportsman Canada has ever sent to this country.

There was no doubt that Ross was very generous with his money and spent a fortune on parties, horse racing and yachts, but there was no single cause for the financial downfall that befell him in 1928, when he was down to his final $300 after inheriting $16 million fifteen years earlier.

Apart from occasional visits to Montreal, he remained in Jamaica, fishing and sailing until his death at his home in 1951 – happier (he told his confidantes), than when he was rich.