McQuillan earned 2011 playing privileges on the PGA Tour with a strong performance in stage three of Q-School, on his first attempt at the finals.

He received instruction at Garrison first in the club's junior program from pro shop manager John Holland, and then privately from assistant professional Kevin Dickey (a former Canadian Tour player).

McQuillan represented Canada for the first time at the 2000 World Junior Team event in Japan, finishing as third individual scorer.

McQuillan graduated from La Salle Secondary School in Kingston, and earned a golf scholarship to Oklahoma State University, beginning in the fall of 2000, where he played for coach Mike Holder.

[4] McQuillan successfully gained PGA Tour status for the 2011 season, by finishing T16 at 11-under-par after six rounds, at final stage, hosted by the Orange County National facility near Orlando, Florida.

[6] McQuillan earned last-minute entry to the Bob Hope Classic in Palm Springs, shot a first-round 7-under-par 65 which included seven birdies and an eagle, but followed up with rounds of 76-73-77 to miss the fourth-round cut with a score of 3-over-par 291.

[7] At the Farmers Insurance Open in San Diego, McQuillan struggled with rounds of 74–77 to miss the halfway cut with a score of 7-over-par 151.

[15] McQuillan played the Nationwide Tour's Stadion Classic at UGA on his former home course in Athens, Georgia, but missed the 36-hole cut by three strokes with scores of 71–76.

[17] McQuillan played the Nationwide Tour's Maryland event, the Melwood Prince George's County Open, and missed the cut by two shots with scores of 72–71.

[19] Although he missed another cut, by four strokes, at the Travelers Championship near Hartford with scores of 73–67, his second round was his first under 70 on the PGA Tour since Pebble Beach, four months before.

He made the halfway cut comfortably with a second-round 69, then played well on the weekend with rounds of 70–64, finishing with 17-under-par 267, to tie for third place, winning $261,000.

[22] McQuillan continued his good play at the Viking Classic, near Jackson, Mississippi, where he scored 72-65-71-67, for 13-under-par 275, to tie for 34th place, winning $18,990.

[23] McQuillan made his third straight cut at the RBC Canadian Open, held over the Shaughnessy Golf & Country Club in Vancouver, scoring 68-73-74-70 for 5-over-par 285, tied for 31st place, and winning $33,800.