Before entering politics he held several leadership roles within Confindustria, at local and national level. Despite being a liberal-conservative, at the 2008 general election Calearo headed the list of the centre-left Democratic Party (PD) and was elected to the Italian Chamber of Deputies. However he soon found that the party was too left-wing for him and in November 2009 took part to the foundation of Alliance for Italy (ApI) with Francesco Rutelli.
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- "Calearo fa il leghista bianco. “Lancio Alleanza per il Veneto” » Rassegna stampa ApI Veneto". Alleanzaperlitalia-veneto.it. Retrieved 2011-06-13.
- "Calearo lascia Rutelli «Da bolscevichi nel Pd minacce di morte»". Archiviostorico.corriere.it. 2009-12-24. Retrieved 2011-06-13.