He was born in Gaziantep. He graduated from the Rüştiye (highscool) in Kırıkhan. During French Mandate in Hatay he participated in opposition movement. But when he was sentenced with death penalty he escaped to Turkey. Although he was pardoned in 1926, next year he escaped to Turkey once more. In 1935 he was elected MP from Antalya Province. When Hatay was declared an independent state Sökmen was elected as the president of the Republic. However soon Hatay merged to Turkey. In later years Sökmen was elected MP from Antalya and Hatay Province up to 1954.
According to Turkish constitution of 1961, former presidents had a seat in the Turkish Senate. Being the former president of Hatay, he became a permanent member of the Senate. However he resigned in 1975. He died in İstanbul.