Mbappe scored his sixth, seventh and eighth goals of the 2022 tournament to take his total to 12 in the competition overall.
He edged out Argentina forward Lionel Messi, who scored twice in the final himself, and ended the World Cup with seven goals as well as being handed the Golden Ball as the tournament’s best player.
Mbappe scored his first of the tournament in France’s opening game, a 4-1 win against Australia. He then scored both in a 2-1 win against Denmark but did not get on the scoresheet in the 1-0 defeat to Tunisia.
Argentina won the final 4-2 on penalties after the game ended 3-3 after extra-time.
Argentina goalkeeper Emiliano Martinez, who won the Golden Glove, saved Kingsley Coman‘s penalty, and Aurelien Tchouameni fired wide to give Argentina their first world title since 1986 and third overall.
France had come from two goals down to level over 90 minutes with Mbappe netting twice in two minutes, including an 80th-minute penalty.
The France striker completed his hat trick in the 118th with another spot-kick after Messi had tapped in for a 3-2 lead in the 109th minute.
Argentina had gone 2-0 up in the first half with Messi, making a record-breaking 26th World Cup appearance, converting a 23rd-minute penalty.
They struck again with a sublime four-pass counter-attack as Alexis Mac Allister‘s cutback found Angel Di Maria and he finished well.
Kylian Mbappe beats Lionel Messi to World Cup Golden Boot award