The club was established by university students from Sinj who had been introduced to football in cities such as Split and Zagreb and who decided to form a club in their hometown.

The name Junak (English: Hero) was chosen as a reply to Hajduk (English: Outlaw), as in Hajduk Split, the name of the well-known club from the nearby city of Split which had been formed five years earlier.

The club's home kit is blue, although they played in black and white kits in the early 20th century as blue cloth was expensive and difficult to come by at the time.

Junak played their very first game on 15 August 1916 and the side was captained by Mirko Kačić.

[1] Note: Flags indicate national team as defined under FIFA eligibility rules; some limited exceptions apply.