France international M'Vila finally completed his protracted move to San Siro from Rubin Kazan on Tuesday.
And Inter boss Walter Mazzarri handed the midfielder his debut in a game that marked the start of the Serie A giants' pre-season preparations.
It took Inter just eight minutes to take the lead through Jonathan and a brace from Mauro Icardi, along with a Federico Bonazzoli strike, gave them a 4-0 half-time advantage.
Teenager Bonazzoli doubled his tally 10 minutes after the restart, before M'Vila came on for the final half an hour.
Trentino grabbed a consolation late on, but there was still more to come from Inter as Juan Jesus notched their sixth of the game in the final minute.
Mazzarri's side will now face Prato on Sunday, before travelling to the United States for a tour that will involve glamour friendlies against Real Madrid, Manchester United and Roma.
Meanwhile, Inter announced on Wednesday that midfielder Lorenzo Crisetig has joined Cagliari on a two-season loan deal.