Col. Villadei joined Italian Air Force (ItAF) in 1993 attending the Air Force Academy in Pozzuoli. He carried out his studies in Aeronautical Engineering with a specialization in space. In February 1999, he was posted as First Lieutenant to the 46th Air Brigade in Pisa and assigned as a Technical Officer on multiple fleets. Among the other activities in his career: from 2018 to 2022, he was national representative at the NATO Science and Technology Office (STO) for Collaborative Space Domain activities;
Walter Villadei is the first Italian to have attended a qualification training as Cosmonaut (2011-12), at the Y. Gagarin State Research & Test Cosmonaut Training Center in Star City. Since September 2021, within an agreement between Italian Air Force and Axiom Space, Col. Villadei commenced his training at NASA as “professional astronaut” and then at mid-2022 he has assigned as Ax2 mission back-up pilot.
On June 29, 2023 Col. Villadei served as VIRTUTE 1 Commander flying suborbital on the Virgin Galactic spaceship from Spaceport America in New Mexico, performing multiple experiments provided by ItAF and the National Research Center.
From January 18 through February 9, 2024 Col. Villadei served as Axiom-3 mission pilot, spending 21 days in space and 18 days aboard the ISS, performing experiments for ItAF, the Italian Space Agency and Italian industries along with some Axiom experiments.
He holds diving certificates (various specialties), VDS piloting license and he is a martial arts instructor.