Bearman stood in for Carlos Sainz in Jeddah after the Spaniard was diagnosed with appendicitis.
Despite not driving the car until final practice – Sainz had driven on Friday – Bearman qualified 11th and finished seventh in the race.
Haas team principal Ayao Komatsu said: “It’s an exciting thing to be able to give a young driver as talented as Oliver Bearman his first full-time seat in Formula 1.
“He’s developed into an incredibly mature driver under the guidance of the Scuderia Ferrari Driver Academy and the world saw that for themselves when he was called in at the last minute to compete at the Saudi Arabian Grand Prix.”
Bearman, who has been a member of the Ferrari driver academy since 2021, will join Lewis Hamilton, George Russell and Lando Norris, meaning 20% of the F1 grid will be British drivers next year.
In addition, Williams driver Alex Albon, who races under the Thai flag, was born in London and has dual Thai-British nationality.
“Oliver proved he was more than ready for the task, and we’ve seen that for ourselves, running him in the Haas cars in our first practice sessions over the past two seasons,” added Komatsu.
“We’re looking forward to further developing him as a driver and reaping the benefits of his talent – both inside and outside of the car.”