The 49 year-old, who took charge of FIFA in February 2016 after the departure of the disgraced Sepp Blatter, stood unopposed for re-election for a new four-year term which will run until 2023.
Ex-president Blatter was in charge for 17 years until he was banned amid a corruption scandal in 2015.
Former Uefa secretary general Infantino was behind the expansion of the World Cup from 32 teams to 48 for the 2026 tournament, which will be held in the United States, Canada and Mexico.
Plans to bring the expansion forward to the 2022 World Cup were however abandoned last month.
In March, Fifa approved Infantino’s plans for a 24-team Club World Cup starting in 2021, despite top European clubs saying they would boycott the tournament.