Tone Peršak candidate for culture minister
The decision, which had been expected, was announced by DeSUS president Karl Erjavec after Wednesday's session of the party's executive committee.
Peršak, a 69-year writer and theatre director, also enjoys the support of his former boss Bizjak Mlakar, who was forced to resign 25 April over a row concerning the UNESCO-listed Idrija mercury mine.
Peršak is now expected to be formally put forward to parliament as ministerial nominee by PM Miro Cerar.
Peršak has been a prominent figure in Slovenian politics and culture for decades. After a spell in politics at the national level in the 1990s, he served for 16 years as mayor of Trzin, a small but wealthy municipality just north of Ljubljana.
In the 1980s he was involved in the democratisation efforts and he co-authored a document known as the writers' constitution, which called for Slovenia's greater sovereignty within Yugoslavia and served as a blueprint for the Slovenian Constitution adopted in 1991.
Peršak was also a co-founder and the first president of the Democratic Party of Slovenia (DS) in 1994-1999 and got elected to the first line-up of the National Assembly (1992-1996). A year later he unsuccessfully stood as a candidate in the presidential election.
He has also made a mark as an author and has served as the president of the Slovenian Writers' Association (2001-2003) and the Slovenian PEN Centre (2004-2009). He has been state secretary at the Culture Ministry since 2014.
As Bizjak Mlakar's chosen successor he had to join the Pensioners' Party (DeSUS). Despite his reluctance to become affiliated with a party, he argued he would do so for the sake of culture.
While being praised as a non-conflict person, some criticise his lack of charisma.