Pergler was born in Liblín, Bohemia, but moved to the United States at a young age.

When his father died, the family moved back to Bohemia, where Pergler got active in the socialist and nationalist movements supporting Czechoslovak independence from Austria-Hungary.

He served as the secretary of Professor Thomas Garrigue Masaryk from May 1918 in America.

He returned to the United States, obtaining a Master of Laws degree from American University.

He would return to Czechoslovakia in 1929, where he worked together with Radola Gajda and Jiří Stříbrný against Edvard Beneš, and got elected to parliament.