Fox finished the four-day event on -23 with a score of 265, ahead of West Australian professional Stephen Dartnell (-17 and 271).
Cottesloe member and Woodlands resident Curtis Luck finished 28th on -7 and a score of 281.
Luck, an amateur player, hit his best round last Saturday when he shot a 5-under 67.
Todd Sinnott, from Victoria, was the highest-placed amateur finishing in sixth position with -13 and 275.
Former Methodist Ladies’ College student Minwoo Lee, an amateur, was 14th with -12 and 276.
The WA Open, hosted by five Perth clubs on rotation, attracted 132 players this year.