Zervas was a Venizelist, and in 1916 was among the first to join the venizelist Movement of National Defense in Thessaloniki. He served with distinction in many battles of the Macedonian front during World War I, being eventually promoted to major.
Zervas was a supporter of the Venizelist Movement, and in 1916 he joined the movement's National Defense effort in Thessaloniki. He served with distinction in numerous battles on the Macedonian front during World War I, eventually being promoted to major rank.