After Mate Boban left the position of president of the Croatian Republic of Herzeg-Bosnia, Zubak succeeded him.

Under Zubak, the Croatian Defence Council and Army of the Republic of Bosnia and Herzegovina established peaceful relations and the Washington agreement was signed.

[3] Before the start of the Bosnian War, Zubak was re-employed at the Ministry of Justice, but returned home after Serb forces attacked the village of Usora.

He was severely wounded during an unsuccessful operation to liberate Doboj, that is, to occupy the strategically important Putnik Hill.

[5] At the general election held in September 1996, Zubak was the Croatian Democratic Union (HDZ BiH) candidate for the Croat seat in the Presidency of Bosnia and Herzegovina.

Even the HSS-NHI, later renamed the Croatian National Alliance of Bosnia and Herzegovina, failed to make any significant political success.

After the general election held in October 2010, Zubak supported the creation of the so-called platform Government of the Federation of Bosnia and Herzegovina without the presence of Croat legitimate representatives.

When the Croatian Democratic Union 1990 (HDZ 1990) refused to join such a government, which included its coalition partner, the Croatian Party of Rights of Bosnia and Herzegovina (HSP BiH), Zubak claimed that HDZ 1990 "is committing political suicide".