Somma started the 2006–07 season as head coach of Brescia in the Serie B, with the aim to lead the rondinelle back to the top flight: however he was sacked in February 2007 as he did not manage to obtain more than a mid-table place.
In October 2009 he returned into football management as new head coach of Triestina, replacing dismissed boss Luca Gotti.
[9] He was however dismissed as head coach only two months later, on 17 August 2014, after only one game in charge of the team (a 0–1 loss to Alessandria in the first round of the 2014–15 Coppa Italia).
[12] On 23 February 2023, Somma returned into management as the new head coach of Serie C club Foggia until the end of the season,[13] only to resign just a month later, on 25 March, following a 1–2 home loss to Monterosi.
[14] On 25 July 2024, Somma moved down to Serie D, accepting the coaching job at newly-promoted club Terracina;[15] however, he resigned only six days later, citing family reasons.