MOSCOW — The leaders of soccer in Europe stood around the marble-floored lobby of a Hyatt hotel in Kiev, Ukraine, last month, trading gossip about one of their former colleagues: FIFA President Gianni Infantino.

Infantino had worked for UEFA, European soccer’s governing body, for nearly two decades, ultimately serving as the organization’s equivalent of a chief executive. Then, in 2016, he became UEFA’s handpicked candidate for his current role, the most powerful job in the sport. But two years later, the warm words and good feelings that had trailed Infantino as he left UEFA’s lakeside headquarters near Geneva to run FIFA have all but evaporated.

In recent months, Infantino has rankled peers, colleagues and even some of his supporters as he has tried to push through major changes to the game, proposing new tournaments that would remake the international schedule. He has offended supporters of women’s soccer by attending a match in Tehran from which women were barred, and he has angered African officials with moves that they felt were designed to hamstring a Moroccan bid to host the 2026 World Cup.

In fact, despite a seemingly endless string of public appearances and globe-trotting the past two years, Infantino remains an enigma: a workaholic administrator who has overseen the repair of FIFA’s most serious financial and operational problems, but one whose rush to change the basic structure of the sport has annoyed enough constituencies that his re-election to a second term next year remains in the balance.