Gastaldello was bought by Juventus in 2002 from Serie C2 side Calcio Padova; in that season, he played in the Primavera squad.

[9] After retiring as an active footballer, Gastadello accepted to stay at Brescia as a coaching staff member.

On 7 December 2020, following the dismissal of Diego López as a head coach, he was named the club's interim head coach,[10] overseeing a 2–2 draw against Cremonese before moving back to his previous role following the appointment of Davide Dionigi as new boss.

On 21 December 2022, Gastaldello was sacked by Brescia with immediate effect following the dismissal of Pep Clotet as head coach.

On 10 November 2023, following a string of negative results that left Brescia in 13th place in the Serie B league table, Gastaldello was however dismissed once again from his coaching post.