Theoren "Theo" Fleury was born in Oxbow, Saskatchewan, and grew up in the small town of Russell, Manitoba, the eldest of three boys.

Fleury grew up playing hockey, overcoming his small stature by adopting an aggressive and determined style of play. As a youth, he played with the St. James Canadians of the Manitoba Junior Hockey League and the Moose Jaw Warriors of the Western Hockey League. He also twice represented Canada in the World Junior Hockey Championships.

The Calgary Flames drafted Fleury in the 8th round, 166th overall, in the 1987 NHL Entry Draft. He scored 34 points in 36 games in his rookie season, helping the Calgary Flames to the first Stanley Cup in franchise history.

Despite emerging as a remarkable talent in professional and international hockey, Fleury's personal life and eventually his career were disrupted by alcoholism, drug abuse, marital, legal, and financial problems, and gambling. In 2003, Fleury was suspended by the NHL for violating the terms of its substance abuse program.

After spending several years working on his sobriety and playing senior hockey in the North Peace Hockey and Elite Ice Hockey leagues, Fleury launched a comeback attempt with the NHL in 2009. He was reinstated to the NHL on September 10, 2009, and was invited for a try-out by the Calgary Flames. He played four exhibition games with the Flames, delighting Calgary fans. The team released him, and he announced his retirement from professional hockey on September 28h, 2009.

Coauthored with Kirstie McLellan Day, Fleury's autobiography, Playing With Fire, was released on October 16, 2009. The book chronicles the highs and lows of his career, as well as the sexual abuse he allegedly suffered as a youth at the hands of disgraced former hockey coach Graham James. The book became a bestseller in his home country of Canada.

Fleury now works with the American organization 1 in 6, which works with men recovering from sexual abuse.