The younger brother of six-time series champion Marc first entered the MotoGP ranks in 2020 with Honda but it was at the British Grand Prix last weekend that he scored his first premier class victory, topping the sprint race.
The result marked his first win since his title-winning Moto2 campaign in 2019 and followed three tricky years on Honda machinery that featured just two podium results.
Despite the victory, Marquez admitted he started the race "a little bit sleeping" as he was overtaken by several riders.
"But, after a few laps I was having good traction and a good feeling with the bike, and I said 'OK, I have to go, I need to make the gap now'," said Marquez, who later suffered a gearshift problem in the main grand prix and was an early retirement.
Marquez added that his brother jokingly called him a "bastard" in the aftermath of the "special" victory, but was "really happy" for his sibling.
The younger Marquez moved across to Gresini for this season and was soon on the pace after the Ducati switch, taking third in just his second event in Argentina.
He has scored two other top-six results this year and was widely expected to remain with Gresini for a second year, and the squad confirmed the renewal on Thursday evening.
It is also expected that Gresini will continue to use Ducati bikes for a third year, having previously had long associations with both Aprilia and Honda.
Marquez's signing follows a busy period of MotoGP driver confirmations that has coincided with the series' resumption from its summer break.
It was revealed last week that Franco Morbidelli would be leaving the factory Yamaha operation at the end of 2023 amid the manufacturer's recent struggles.
This was followed by news that Alex Rins would exit Honda a year early to take Morbidelli's place at Yamaha.
Morbidelli's team-mate, 2021 champion Fabio Quartararo, has meanwhile said that he will make a decision on his future following a crucial Misano test in October.
