Armstrong joins Hitech for his third year in the series, having raced for ART in 2020 before switching to compatriots DAMS for 2021.
Hitech thus completes its line-up for 2022 after retaining the services of Red Bull junior Juri Vips, while Liam Lawson has left the British team to join Carlin.
After a difficult couple of seasons in F2, Armstrong secured his breakthrough win at the opening Jeddah sprint race after holding off compatriot Lawson, helping him secure 13th in the drivers' standings.
“I’m thrilled to be joining Hitech this season in Formula 2,” said Armstrong.
“Team principal Oliver Oakes brought me to Europe a few years back and I saw Hitech in the early days. Since then, it’s transformed into one of the powerhouses of Formula 2 and 3.
“I’m looking forward to be working with a successful group of people and giving it everything I’ve got in my new Hitech team this year.”
It was announced previously that the Ferrari Driver Academy and Armstrong would part ways following the Kiwi's five-year stint on the programme, joining it after winning the Italian F4 title.
Armstrong then moved up to European F3 - remaining with the Prema team that helped him to glory in F4 - and stayed with Rene Rosin's outfit for FIA F3 as it transitioned from the old GP3 series in 2019.
Battling against team-mates Robert Shwartzman and Jehan Daruvala for the title, Armstrong finished as runner-up to Shwartzman with three victories across the season.
Securing his promotion to F2, Armstrong endured a difficult 2020 with ART despite a bright start in which he managed two podiums at the Red Bull Ring's opening pair of rounds, before moving to DAMS.
Armstrong's signing comes as the 2022 F2 grid is beginning to fill up, with Jake Hughes' signing on Monday proving to be the first for the incoming Van Amersfoort Racing.
VAR has its second drive to fill, with ART, Campos, Trident and Charouz also with one vacant seat each.
