In 1942, Sismey was seriously wounded when the flying boat of which he was the co-pilot was attacked by fighter aircraft of the Vichy French Air Force, over the Mediterranean Sea off Algeria.

These injuries sometimes affected Sismey long after his recovery: he had to leave a ground during at least one game, because a piece of metal had begun to work its way out of his body.

[6] He made his debut for NSW on 15 December 1939 against South Australia – led at the time by Don Bradman – at Adelaide Oval.

[14] He was considered a contender to succeed Bert Oldfield as the wicketkeeper of the national team when the war intervened;[13] there were no official international matches involving Australia between 1940 and 1946.

[13] On 21 November 1945, as a result of his war wounds, Sismey underwent an operation at a hospital in Bombay (later Mumbai) to remove a metal fragment that was working its way out of his body.

"[19] Sismey was also kept out of the NSW team by Saggers, before being re-selected during the 1949/50 season, when his keeping also earned him selection for an unofficial Australian Second XI that toured New Zealand.

[13] There Sismey played for Clydesdale Cricket Club, as well as one game for the national team of Scotland, during 1952[6] against Yorkshire at Hamilton Crescent, Glasgow.

[4] The Catalina crew spent eight hours in the sea, and Sismey was unconscious[6] by the time they were picked up by the British destroyer HMS Ithuriel.

[6] On at least one occasion after he resumed playing cricket, Sismey had to leave the ground during a game because a metal fragment had suddenly worked its way out of his body.

[6] Sismey did not return to operational flying duties for more than two years,[13] when he was offered a posting to a RAF unit as a test pilot.

[22] His younger brother, Frank (Francis Leonard Sismey; born 1918), was killed on 20 May 1945, while piloting a RAAF Liberator heavy bomber that crashed while taking off, at Truscott Airfield, in the extreme north of Western Australia.