The Englishman earned his place in the field by defeating Robert MacIntyre, 2 and 1, at Royal Porthcawl in the championship match of the 2016 Amateur Championship conducted by The R&A. The victory earned Gregory a spot in the 2016 Open Championship at Royal Troon, where he missed the cut despite being 4 under par through his first 10 holes. His Amateur victory also earned him an invitation to the 2017 Masters Tournament. He qualified for match play in last year's U.S. Amateur at Oakland Hills, but was eliminated in the Round of 32 by eventual semifinalist Nick Carlson. He was the runner-up in the 2014 English Amateur and 2016 Spanish Amateur.