Born on the 8th October 1914, Feyzi was raised in Tuusula near Helsinki. He was a university student focusing upon Tatar history. He attended the 40th Reserve Officer School course, graduating with the rank of Kornetti (Cornet). He served in the Uusimaa Dragoon Regiment from 1938 to 1939. He wasn’t the only member of his family to serve, his two brothers were also officers and saw service during the Winter War.
He was assigned as a platoon commander in Separate Battalion 9 when the Winter War broke out. He proved himself during fierce fighting at Uomaa, including conducting a behind the lines reconnaissance mission.
He moved with the rest of the battalion to fight at Tolvajärvi. After the victory at Tolvajärvi, Detachment P pushed on to Ägläjärvi. On the morning of the 20th December, Cornet Feyez Kayenuk was wounded and taken to a dressing station. His wounds proved to be fatal and after a few hours he succumbed to them.