Born in Gardone Val Trompia, Cittadini started playing at Lumezzane before joining Atalanta's youth sector in 2016, aged 14.[1] Although he did not play consistently until he joined the under-17 team, he progressively came through the club's youth ranks,[2][3] winning a national championship and two Super Cups with the under-19 team in 2020 and 2021.[1][4]
On 9 January 2022, Cittadini made his professional debut for Atalanta, coming in as a 90th-minute substitute in a 6–2 Serie A win against Udinese.[5]
Loan to Modena
On 7 July 2022, Cittadini joined newly-promoted Serie B club Modena on a season-long loan.[6] Throughout the 2022–23 season, he established himself as a regular starter in the side, being praised for his league performances.[1]
Loan to Monza
On 4 July 2023, Cittadini was sent on a one-year loan to Monza ahead of the 2023–24 Serie A season.[7]
Loan to Genoa
On 26 January 2024, Cittadini moved on a new loan to Genoa.[8]
Loan to Frosinone
On 17 July 2024, Cittadini joined Frosinone on loan.[9]
In June 2022, he received his first call-up to the under-20 national team,[11] subsequently making his debut with the Azzurrini on June 7, coming in as a substitute during the 1–0 home loss against Poland.[12]
Cittadini is a centre-back, who can play either in a back four or in a back three: he has been mainly regarded for his strength, his positioning and his ball-playing skills.[1][3]