Cardile will work under managing technical partner Adrian Newey, who started work in March after leaving Red Bull last year.
Newey has been leading work on the car Aston Martin are designing for the 2026 rules, and the start of their new factory deal with engine partner Honda.
Fernando Alonso and Lance Stroll will continue to drive for Aston Martin next year. The Spaniard is entering the last year of his contract and will turn 45 in July 2026.
Alonso has previously said he will go into 2026 thinking it will be his last year in F1, but is keeping an open mind as to whether he might want to continue longer.
“Probably – or at least to start – it will be my last season in F1,” he told BBC Sport last December. “Because my contract finishes at the end of 2026. It is the time of delivering and the time of truth. High expectations.”