During the expedition, Crean's 35-statute-mile (56 km) solo walk across the Ross Ice Shelf to save the life of Edward Evans led to him receiving the Albert Medal.

After his experience on the Terra Nova, Crean's third and final Antarctic venture was as second officer on Ernest Shackleton's Imperial Trans-Antarctic Expedition.

After retiring from the navy on health grounds in 1920, Crean ran his pub the South Pole Inn in County Kerry with his wife and daughters.

Many sources, including Smith, give Crean's date of birth as 20 July 1877,[3] but more recent scholarship demonstrates this is unlikely given parish records.

In December 1894, Crean was posted to HMS Wild Swan a screw sloop as the ship headed to South America to join the Pacific Station.

In 1895, Crean was serving in the Americas aboard HMS Royal Arthur, the flagship assigned to the Pacific squadron's base at Esquimalt in Canada.

[6][9] In December 1901, the Ringarooma was ordered to assist Robert Falcon Scott's ship Discovery when it was docked at Lyttelton Harbour awaiting to departure to Antarctica.

[10] Discovery sailed to the Antarctic on 21 December 1901, and seven weeks later, on 8 February 1902, arrived in McMurdo Sound, where she anchored at a spot which was later designated "Hut Point".

Scott's second-in-command, Albert Armitage, wrote in his book Two Years in the Antarctic that "Crean was an Irishman with a fund of wit and an even temper which nothing disturbed.

These included the 12-man party led by Barne which set out on 30 October 1902 to lay depots in support of the main southern journey undertaken by Scott, Shackleton and Edward Wilson.

[6][17] Crean came back to regular duty at the naval base at Chatham, Kent, serving first in Pembroke in 1904 and later transferring to the torpedo school on Vernon.

"[20] Scott held Crean in high regard,[21] so he was among the first people recruited for the Terra Nova Expedition, which set out for the Antarctic in June 1910, and one of the few men in the party with previous polar experience.

[17] After the expedition's arrival in McMurdo Sound in January 1911, Crean was part of the 13-man team who established "One Ton Depot", 130 statute miles (210 km) from Hut Point, so named because of the large amount of food and equipment cached there on the projected route to the South Pole.

[24] At regular intervals, supporting parties returned to base; Crean was in the final group of eight men that marched on to the polar plateau and reached 87°32'S, 168 statute miles (270 km) from the pole.

[32] With over 100 statute miles (160 km) still to travel before the relative safety of Hut Point, Crean and Lashly began hauling Evans on the sledge, "eking out his life with the last few drops of brandy that they still had with them".

With only a little chocolate and three biscuits to sustain him, without a tent or survival equipment,[34] Crean walked the distance to Hut Point in 18 hours, arriving in a state of collapse to find Atkinson there, with the dog driver Dmtri Gerov.

[39] On 12 February 1913 Crean and the remaining crew of the Terra Nova arrived in Lyttelton, New Zealand, and in June the ship returned to Cardiff.

[2] At Buckingham Palace the surviving members of the expedition were awarded Polar Medals by King George V and Prince Louis of Battenberg, the First Sea Lord.

[40][41] Crean and Lashly were both awarded the Albert Medal, 2nd Class for saving Evans's life, these were presented by the King at Buckingham Palace on 26 July.

Shackleton informed the men that they would drag the food, gear, and three lifeboats across the pack ice, to Snow Hill or Robertson Island, 200 statute miles (320 km) away.

They hoped that the clockwise drift of the pack would carry them 400 statute miles (640 km) to Paulet Island where they knew there was a hut with emergency supplies.

After the party was settled on a penguin rookery above the high-water mark, a group of men led by ship's carpenter Harry McNish began modifying one of the lifeboats—the James Caird—in preparation for this journey, which Shackleton would lead.

Shackleton, in his later account of the journey, recalled Crean's tuneless singing at the tiller: "He always sang when he was steering, and nobody ever discovered what the song was ... but somehow it was cheerful".

[57] The original plan was to work the James Caird around the coast, but the boat's rudder had broken off after their initial landing, and some of the party were, in Shackleton's view, unfit for further travel.

The three fittest men—Shackleton, Crean, and Worsley—were decided to trek 30 statute miles (48 km) across the island's glaciated surface, in a hazardous 36-hour journey to the nearest manned whaling station.

[59] They arrived at the whaling station at Stromness, tired and dirty, hair long and matted, faces blackened by months of cooking by blubber stoves—"the world's dirtiest men", according to Worsley.

[60] They quickly organized a boat to pick up the three on the other side of South Georgia, but thereafter it took Shackleton three months and four attempts by ship to rescue the other 22 men still on Elephant Island.

On 27 December 1916 he was promoted to the warrant rank of acting boatswain (confirmed in 1918) in recognition of his service on the Endurance,[6][62][63] and was awarded his third Polar Medal.

[70] On 13 April 1920, Crean was present among crowds gathered in Tralee to protest against the treatment of republican prisoners who had gone on a hunger strike in Mountjoy jail.

[81] In February 2021 it was announced that a new research vessel being commissioned by the Irish government's Department of Agriculture, Food and the Marine would be named RV Tom Crean.