Crean leaves the family farm to enlist in the Royal Navy at the age of fifteen. In 1901, while serving on Ringarooma in New Zealand, he volunteers to join Captain Robert Falcon Scott‘s 1901–04 Discovery Expedition to Antarctica, thus beginning his exploring career.
He is a member of three major expeditions to Antarctica during the Heroic Age of Antarctic Exploration, including Captain Scott’s 1911–13 Terra Nova Expedition. This sees the race to reach the South Pole lost to Roald Amundsen and ends in the deaths of Scott and his polar party. During this expedition, Crean’s 35 statute miles solo walk across the Ross Ice Shelf to save the life of Edward Evans leads to him receiving the Albert Medal for Lifesaving.
After his Terra Nova experience, Crean’s third and final Antarctic venture is as second officer on Ernest Shackleton‘s Imperial Trans-Antarctic Expedition, on Endurance. After Endurance becomes beset in the pack ice and sinks, Crean and the ship’s company spend months drifting on the ice before a journey in boats to Elephant Island. He is a member of the crew which makes an open boat journey of 800 nautical miles from Elephant Island to South Georgia, to seek aid for the stranded party.
Crean’s contributions to these expeditions seals his reputation as a polar explorer and earns him a total of three Polar medals. After the Endurance expedition, he returns to the navy. When his naval career ends in 1920 he moves back to County Kerry. In his home town of Annascaul, Crean and his wife Ellen live quietly and unobtrusively and open a pub called The South Pole Inn.
In 1938 Crean becomes ill with a ruptured appendix. He is taken to the nearest hospital in Tralee, but as no surgeon is available to operate, he is transferred to the Bon Secours Hospital in Cork where his appendix is removed. Because of the delay of the operation an infection develops and after a week in the hospital he dies on July 27, 1938, shortly after his sixty-first birthday. He is buried in his family’s tomb at the cemetery in Ballynacourty.
Crean’s name is commemorated in at least two places – 8,630 foot Mount Crean in Victoria Land and the Crean Glacier on South Georgia. A one-man play, Tom Crean – Antarctic Explorer, has been widely performed since 2001 by its author Aidan Dooley, including a special showing at the South Pole Inn, Annascaul, in October 2001. In July 2003, a bronze statue of Crean is unveiled across from his pub in Annascaul. It depicts him leaning against a crate whilst holding a pair of hiking poles in one hand and two of his beloved sled dog pups in the other.