[3][4] When Longboat was a child, a Mohawk (Kanienʼkehá꞉ka) resident of the reserve, Bill Davis, who in 1901 finished second in the Boston Marathon, interested him in running races.

In 1907 he won the Boston Marathon in a record time of 2:24:24 over the old 24+1⁄2-mile (39.4 km) course, four minutes and 59 seconds faster than any of the previous ten winners of the event.

Although this was public knowledge, reporters and fans often blamed "Indian laziness" for his occasional poor showing.

While many newspaper columns were devoted to his supposed alcoholism, the facts of Longboat's racing career and post-athletic work appear to be in strong contradiction.

[9] Members of his family did not believe how fast he could run over such a long distance until he gave his brother a half an hour head start driving a horse and buggy while he ran on foot, and yet he still made it to Hamilton first.

Stories said that he had entered a communication trench which was buried by an exploding shell, where he and his comrades were trapped for six days (albeit with sufficient oxygen and provisions) before being rescued.

[10] He was enrolled at the Mohawk Institute Residential School at age 12, a legal obligation under the Indian Act at that time.

From late 1916 until the summer of 1917, a white Rhode Island-born vaudeville singer, conman and onetime medicine show performer named Edgar Laplante (1888-1944) travelled around America pretending to be him and giving concerts that profited from Longboat's continued celebrity.

In August 1917 Laplante arrived in New York City, where he enrolled under Longboat's name as a civilian crewman with the U.S. Army Transport Service.

During Laplante's initial voyage aboard the S.S. Antilles, a debate raged in the Brooklyn Daily Eagle regarding whether the real Longboat was in France or serving with the U.S. Army Transport Service.

Eventually, Longboat heard about the impostor's antics and wrote a letter about them, which ended up being quoted in several American newspapers.

"I am going to have three charges against this man, one for making false statements, second for impersonation, third [for] intent to defraud the public at large.

"[14] When erroneous reports reached America that Longboat had been killed in action while serving with the CEF in France, the consequent American newspaper stories were often illustrated by photos of the imposter, Edgar Laplante.

[23][7] Google's 4 June 2018 Doodle celebrates the life and legacy of Tom Longboat, and was distributed across Canada and the United States.

[26] A fictionalized version of Longboat appears as a long-distance runner in two season 12 episodes of the CBC Television period drama Murdoch Mysteries, in "Darkness Before the Dawn" parts 1 and 2.