At age 30, he was selected by Teddy Evans to join the Terra Nova Expedition to Antarctica. He joined the Terra Nova from HMS Repulse. On the expedition's main southern journey, he led a pony to the foot of the Beardmore glacier, and then became part of the 12-man manhauling party which began the push towards the pole. He was a member of the first supporting group, along with Edward L. Atkinson, Charles S. Wright and Apsley Cherry-Garrard, to be sent back at 85° 15’ South on 22 December 1911. On their journey back to Cape Evans, Keohane fell down crevasses to the full length of his harness eight times in twenty five minutes. According to Cherry-Garrard, Keohane “looked a bit dazed” after that ordeal. They successfully reached Hut Point on 26 January 1912.
On 27 March 1912, Keohane, along with Atkinson, attempted to find Scott and his polar party and bring them back to Cape Evans from the One Ton supply depot. Starting at Hut Point, the party only made it to a point eight miles south of Corner Camp. There they left a weeks provisions and returned to Cape Evans on 1 April.
On 29 October 1912, after spending the winter on the continent, Keohane was among a party that went to search for Scott’s group. On 12 November, they found the frozen bodies of Scott, Edward Adrian Wilson, and Henry Robertson Bowers eleven miles south of the One Ton supply depot.
He later rejoined the Royal Navy and served in World War II.
He died in Plymouth, England in 1950 at the age of 71.
- Scott, Robert Falcon (2006). Robert Falcon Scott Journal's: Captain Scott's Last Expedition. Oxford England: Oxford World's Classics, Oxford University Press. ISBN 0-19-929752-5.
- Rosove, Michael H. (2000). Let Heroes Speak. Annapolis, MD: Naval Institute Press. ISBN 1-55750-967-0.
- Huxley, Elspeth (1978). Scott of the Antarctic. New York, NY: Atheneum. ISBN 0-689-10861-3.
- Cherry-Garrard, Apsley (2006). The Worst Journey in the World. New York, NY: Penguin Classics. ISBN 0-14-303938-5.
- Huxley, Elspeth (1978). Scott of the Antarctic. West Hanover and Plympton, Massachusetts: Halliday Lithograph Corporation. ISBN 0-689-10861-3.