The 'Cherry and Whites' scored three tries one, with inside centre Henry Paul, one of the try-scorers, converting two of their five-pointers – also adding two penalty goals, along with a Duncan McRae drop-goal.
Paul opened the scoring in the second minute with a try, courtesy of a kick-ahead from McRae, which Paul converted, before McRae slotted his drop-goal in the seventh minute.
To their credit, however, London Irish fought back. First fly-half Barry Everitt slotted a penalty in the 12th minute and then one-time England fullback Michael Horak got over for a try, which Everitt converted to draw the scores level at 10-10.
Both kickers exchanged penalties shortly before half-time, but the home side had the final say before the break when hooker Chris Fortey drove over from a line-out in the 40th minute.
Paul could not convert, but a penalty 14 minutes into the second half put the 'Cherry and Whites' more than seven points up – at 21-13 – for the second time in the game.
Some determined defence from the Exiles kept Gloucester at bay, but when speedy England winger James Simpson-Daniel crashed over well into injury-time (with Paul, again, converting), the result was put beyond any doubt.
For Gloucester:Tries: Paul, Fortey, Simpson-DanielCons: Paul 2Pens: Paul 2DG: McRae
For London Irish:Try: HorakCon: EverittPens: Everitt 2