Cathro, 39, started his coaching journey in his home city Dundee – nurturing the likes of Ryan Gauld and John Souttar in Dundee United’s academy – before moving to Portugal to become Nuno Espirito Santo’s assistant at Rio Ave.
He would follow Nuno to Valencia, before working under Steve McLaren and Rafael Benitez at Newcastle United.
Then came his ill-fated seven-month stint with Hearts in 2017, which ended after he failed to get out of the League Cup group stages.
However, he put that experience behind him – again linking up with Nuno at Wolverhampton Wanderers, Tottenham Hotspur and Al-Ittihad.
Cathro returned as a head coach with Estoril in the summer of 2024, guiding them to an eighth-placed finish in Portugal’s top flight before finishing 10th last season, playing some of the most attractive football in the division.
“Ian has forged a unique career path,” Saint-Etienne president Ivan Gazidis said.
“He doesn’t arrive with a conventional trajectory, but with a wealth of experience in coaching, player development, and various football cultures.
“We were particularly impressed by his ability to give a team a clear direction, to help players progress, and to create a demanding working environment.
“At Estoril, he showed that he could move a club forward with method, identity, and stability. This is precisely what we want to establish at AS Saint-Étienne.”