A centre back with free kick abilities, Dionisi spent most of his career at Serie C2 and Serie D levels, with his highlight being at Tritium, a club he captained and with whom he won promotion to Lega Pro Prima Divisione and also played in the Italian third tier for a season.
His impressive results with Imolese won him the attention of Venezia, who appointed him head coach on 3 July 2019.
[4] His impressive results at Empoli led to Serie A club Sassuolo offering him the vacant role of head coach after Roberto De Zerbi's departure; after rescinding his contract with Empoli on 15 June 2021,[5] Dionisi signed a two-year deal with Sassuolo the following day, effective from 1 July 2021.
[6] After guiding Sassuolo to two consecutive mid-table placements in the Serie A, Dionisi was sacked on 25 February 2024 following a string of negative results that left the Neroverdi struggling in the bottom positions of the league.
[7] On 7 June 2024, Dionisi was unveiled as the new head coach of Serie B promotion hopefuls Palermo.