The 19-year-old won the competition by one stroke, but his one-under-par gross 71 was three shots better than the rest of the field.
Parkman, a former Junior Island Golfer of the Year, said: ‘It was my first big Jersey Golf Union senior win and I was delighted.
It felt good to win the scratch section by three shots and the handicap by one.
‘I have been hitting the ball well of late, but I’ve been a bit impatient.
Everything seemed to click on the day and hopefully I can maintain my form this weekend in the Island championship.
‘I like the La Moye course because it’s long and open, so if you get into trouble the openness makes recovery a bit easier.’ Parkman reached the turn in level par after being one under through three, and after bogeys at four and five he gained another birdie at the sixth.
A bogey followed at ten and a birdie at 11 before pars through to 17 before he holed a 20-foot putt for birdie at the last.
