Polls make the bearded retired general, 61, the favourite to win a run-off vote on Friday and Saturday against billionaire ex-prime minister Andrej Babis, 68.
"We got into several tense situations and he always managed them with deliberation and calm," retired Czech general Ales Opata, who served in Croatia and after with Pavel, told Reuters.
He lead the Czech general staff from 2012, during Czech involvement in operations in Afghanistan, and in 2015 became NATO's military committee chair, an advisory position of the alliance's secretary-general.
Jiri Sedivy, chief executive of the European Defence Agency and former Czech ambassador to NATO, said Pavel was a decision-maker who could take responsibility.
After Russia's 2014 annexation of Crimea, Pavel represented NATO in a 2017 meeting with Russian Chief of General Staff Valery Gerasimov.