The article deals with the influence of presidents in the government formation process (GFP). The authors propose an original classification of roles of presidents, reflecting real constitutional practice, with five categories based on real presidential influence on the GFP, from the weakest to the strongest: observer, notary, regulator, co-designer, and creator. This classification is applied to Czechia, where the formal constitution gives the president great opportunities to intervene in the GFP. The results of the analysis of all cases of GFP show a significant variety of roles the Czech presidents have played: from notary to creator. Two factors are particularly important. Firstly, the timing of elections proved significant. When the GFP directly followed parliamentary elections, the presidents were weaker. In contrast, if the GFP followed a government break-up during the electoral term of the Chamber of Deputies, presidents were significantly stronger. Secondly, it depends on the real power of parties, that is, their ability to act together as a cohesive parliamentary majority. In most cases, the presidents showed their resolve to play a greater role than a notary, but they often faced a firm parliamentary majority that actually did not allow them to exert greater influence on the GFP. In contrast, the political proximity between the president and parliamentary parties appears difficult to assess, because there has been the public desire of non-partisan or “above-partisan” presidents in Czechia.