Fischer, 65, the deputy parliamentary speaker who will now become Austria's first socialist president in 18 years, defeated on Sunday Benita Ferrero-Waldner, who is from Schuessel's People's Party (OeVP) and was also backed by far-right nationalist Joerg Haider.
Fischer vowed after the vote, for what is a largely ceremonial post, to "work to look after the interests of all Austrians. That is my firm intention."
Ferrero-Waldner, 55, said she was bitterly disappointed but would continue to serve as foreign minister. Fischer won 52.41% of the vote to 47.59% for Ferrero-Waldner in the direct election, in what amounted to a difference of only 200,000 votes out of the some four million cast, Interior Minister Ernst Strasser told a press conference.
Schuessel said he was "proud" of Ferrero-Waldner for coming so close, and said there could have been a "surprise" if voter
participation had been higher.
Turnout on Sunday was 70.76%, down from 74.40% in the last presidential election in 1998.
Fischer, 65, will succeed conservative Thomas Klestil on 8 July. He will be the central European country's first socialist president since Rudolf Kirchschlaeger, who left office in 1986.
The result could have an effect on Schuessel, who is about
halfway through his term and whose party last month lost two crucial regional elections.
Fischer's win was already being proclaimed by socialist leaders
as yet another sign that Schuessel's popularity is fading.