Magnesi made his professional debut on 10 October 2015, scoring a four-round points decision (PTS) victory against Carmelo Palermo at Palasport V.le Tiziano in Rome, Italy.

[4] After compiling a record of 11–0 (4 KOs), he defeated Francesco Invernizio via third-round technical knockout (TKO), capturing the vacant Italian super-featherweight title on 30 June 2018 at the Piazza Dante in Grosseto, Italy.

[8] He next defeated Emanuel López via tenth-round knockout (KO) on 21 June, capturing the vacant WBC International Silver super-featherweight title at the Parco della Pace in Rome.

[9] Following a stoppage victory against Maxwell Awuku in a non-title fight in October,[10] Magnesi won his third regional title on 29 February 2020 after defeating Breilor Teran via fourth-round RTD to capture the vacant IBO Inter-Continental super-featherweight title at the Tiburtina TV Studios in Rome.

[11] In his next fight he faced Patrick Kinigamazi for the vacant IBO super-featherweight title on 27 November 2020 in Fondi, Italy.