Moreno began his playing career with Lascaris youth team before moving to Torino in 1987, with whom he made his debut in Serie A in 1994–95 during a 5–1 defeat against A.C. Milan.

He played 18 times for the club in the cadets, but was also involved in the Torneo di Viareggio as part of the youth team, lost in the final against Bari.

The following year, he moved to Canavese, and achieved qualification for the knockout phase of the national championship in the same age group.

[5][6] In the 2013–14 season, his squad finished as runners-up in the Campionato Nazionale Primavera, after losing the final 4–3 on penalties to Chievo.

On 22 January 2021, Longo accepted the manager's job at Serie C club Alessandria, another former team of his as a player, signing a 2.5-year contract.

[13] Under his tenure, he guided Alessandria to second place in the Girone A group, then winning the national playoff phase after defeating Padova on penalties in a two-legged final and ensuring the Grigi a Serie B spot for the first time in 45 years.

[14] Alessandria was relegated back to Serie C at the end of the 2021–22 season; on 29 July 2022, Longo mutually rescinded his contract with the club.