Puskar participated in World War I, joining the Estonian national units in 1917.

At the beginning of the Estonian War of Independence in 1918, Puskar was leader of the Järvamaa Defence League.

During the war he successfully defended South Estonia, expelled the Red Army from North Latvia and captured Pskov.

He was one of the leaders of the Vaps Movement and was in jail from 1936 to 1937, accused of underground activity.

Puskar went to Germany in 1941, returning to Estonia after the Red Army had been driven out.