After Greek army began invading Turkish territory on 15 May 1919, he began to fight against the regular Greek troops as a guerrilla fighter under the general principles of Turkish National Movement (Turkish: Kuvai Milliye).
During the summer of 1919, he fought successfully against the Greek troops usually with hit-and-run tactics.
In November, he tried to confront a Greek advance in the village Fata near Ödemiş.
But, at the end of a three-day fighting, he fell on 16 November 1919.
[2] In 1957, Turkish government renamed the town of Fata, after merging with another settlement, to Gökçen in his honor.