Pat was born in Northern California, started drummering at 10 and moved to Los Angeles at 17.
First top ten pop record was Martin Briley in 1980.
After providing beat bravado for four Mr. Mister albums and two #1 singles: "Broken Wings" and "Kyrie", Mastelotto accepted an invitation to provide the backbeats for XTC, Cock Robin, The Rembrandts (#1hit), Jude Cole, Tina Arena, Michael Penn, Hall & Oats, Pointer Sisters, Patti Labelle, Robyn Hitchcock, the Sugercubes and in 1993 David Sylvian and Robert Fripp.
In 1994 The double trio formation of the legendary KING CRIMSON. Mastelotto partnering Bill Bruford, Adrian Belew, Tony Levin, Trey Gunn and Robert Fripp.
In 2000 the double duo (Belew/Fripp/Gunn.
In 2008 with Belew/Fripp/Tony Levin joined by Gavin Harrison and Pat on drums
Since moving to Austin, Texas he continues his outside work for an international clientele like Steven Wilson, Kimmo Pohjonen, Markus Reuter, Lorenzo Feliciati , John Paul Jones, Flower Kings, Steve Hackett, Peter Kingsbery, Isuldurs Bane and also local Austinites Trail of the Dead, Abra Moore, Chrysta Bell, Malford Milligan, Mastica.
Pat has spent a lifetime jumping genres from pop, to prog-rock ,to electronica to world music and the unlimited boundaries of Crimson providing a natural segue for Mastelotto's entry into one of the more extreme improvised experiments : HoBoLeMa - with Alan Holdsworth, Terry Bozzio and Tony Levin.