From 2000 to 2006 Miletić served in various civil service positions in Istria County, including an internship with the Department for the Economy (2000–2001) and with the Istrian Development Agency (2001–2006), where he would eventually become CEO.
In 2014, after the expulsion of Damir Kajin from the IDS, Miletić became party's leader.[3] In the 2015 parliamentary election, Miletić and party leaders decided to leave the Kukuriku coalition (afterwards known as the Croatia is Growing coalition) and have the party contest the election on its own.[4] The party would go on to win three seats.
After the local elections in 2021, Miletić resigned as party president after the heavy defeat of the IDS in municipal elections in Pula.[5]
In 2022, the IDS presidency initiated disciplinary proceedings against Miletić, after which he left the party.[6]