The 29-year-old Inverness, Scotland, golfer turned pro in 2007 after graduating from Jacksonville University in Florida and he also came through the Paul Lawrie Foundation, the sporting centre of excellence founded by the Ryder Cup player with whom Glenmuir enjoyed a long association until last year.
Duncan made every cut in 15 events on the PGA EuroPro Tour last year to finish second and qualify for the Challenge Tour, a period during which he won the Sweetspot Classic and Sweetspot Masters as well as securing a lucrative third place in the 888Poker.com Tour Championship finale at Woburn.
Attached to Grantown on Spey GC, Duncan is on track to complete his dream of playing at the highest level on the European Tour, alongside countrymen like Lawrie and emerging stars Scott Jamieson and Peter Whiteford.
Announcing the agreement, Glenmuir managing director, Colin Mee, said: "We're always happy to try and support young, Scottish, golf talent and Duncan is a golfer who looks to have all the attributes to become a very successful Tour player.
"The fact that he came through the ranks at the Paul Lawrie Foundation is also extremely pleasing. Glenmuir enjoyed a happy association with Paul for many years and Duncan's progression is testament to the success that the foundation has in nurturing young sportspeople and helping them to achieve their goals in life.
"We're delighted to be playing a part in the next exciting phase of Duncan's journey and we wish him every success."