Between July and October 2004, he served as speaker of the Slovenian National Assembly.

He was born as Franc Horvat in a Slovene Lutheran family in the village of Kuštanovci in the Prekmurje region of eastern Slovenia (then part of the Horthy's Hungary).

In the 1960s and 1970s, he served as director of several Slovenian companies, both in the industrial and financial sector.

After the dissolution of Yugoslavia in 1991, Horvat returned to Slovenia, where he was among the co-founders of the United List of Social Democrats, a left wing party which was established by the merger of the former League of Communists of Slovenia and other minor leftist parties.

In 1992, he was elected to the Slovenian National Assembly (the lower house of the Parliament of Slovenia).