He was invited to come under the wing of Tom Simpson during the early 1920s, working mainly on overseas projects such as the courses at Royal Antwerp and Royal Fagnes in Belgium, Deauville and Hardelot in France, as well as Malaga in Spain.

Ross was a founding member of the International Society of Golf Architects, along with architects such as John Abercromby, C.H. Alison, Harry Colt, Herbert Fowler and Alister MacKenzie. Formed in 1929, the society operated from secretary Tom Simpson’s office at his home in England.

Branching out on his own during the 1930s, Ross developed strong Iberian connections, travelling to Miramar and Vidago Palace near Porto and to Estoril, close to Lisbon. He also laid out the original 9-hole course at Furnas on the island of San Miguel in the Portuguese Azores.

After World War II, Ross helped restore many courses around the British Isles that had been damaged or neglected during the conflict, travelling to places like Royal Guernsey in the Channel Islands, Castletown on the Isle of Man and Pyle & Kenfig in Wales.

Of course, his most famous commission was the restoration of the Ailsa course at Turnberry, revitalising a layout that had suffered more than most during the war effort due to its use as a busy airfield.

Some of his assignments were completed in partnership with John Hamilton Stutt – son of John R. Stutt who built dozens of courses for James Braid – but Stutt gave up the family construction business during the 1950s to concentrate solely on design.

During this time, Ross returned to Portugal to work at Oporto, one of the oldest clubs on the continent, and he also laid out a couple of new courses on Gran Canaria, at Maspalomas and Real Las Palmas. He also went back to France to renovate the 18-hole La Forêt layout at Golf du Touquet in France.

There wasn't a lot of work for him in the 1960s (when he was by that time in his seventies) apart from some advisory visits to clubs where he had previously worked.

Extracts:

"P. M. Ross learned golf at Royal Musselburgh and won several amateur medals as a youth. He served with the British Army during World War I and upon discharge looked for a golf-related job. By chance he met golf architect Tom Simpson, who hired him as a construction boss in 1920. By the mid-Twenties, Ross was a full partner in the firm of Simpson and Ross." The Golf Course Geoff Cornish and Ron Whitten

“Mackenzie Ross was not as prolific an architect as many of his competitors, yet the courses he designed or remodelled illustrated his genius, each layout having a considerable impact on modern golf course design. His skill was his ability to see the potential in a site and then maximise it.

He wouldn’t make a decision until he had considered it hard and long. He would explore the alternatives, weigh up the benefits and constraints, and only then would he eventually commit himself to a layout for the course.

His work can be regarded as of equal merit to that of such legendary contemporary architects as Fowler, Colt, MacKenzie and Simpson.

They all understood the intricacies of the game itself, and they studied closely the designs of the older courses from which they found inspiration. They all seemed to possess a similar vision – to maintain the mystique of the game, and to keep this element alive.” Jonathan Gaunt in a Golf Course Architecture article from April 2007.

Donald Steel commented as follows in the foreword to the book Simpson & Co. Golf Architects by Fred Hawtree:

“The scene from Philip Mackenzie Ross’s house, overlooking the links of North Berwick, was one of uninterrupted splendour. During the Open Championship at Muirfield in 1972, a kind invitation to visit a one-time pupil of Simpson, in my humble position as Honorary Secretary of the recently formed British Association of Golf Course Architects. Mackenzie Ross was its first President.

Apart from his considerable physical stature, the first thing that struck me was his affinity for collecting antique golf clubs and malt whiskies, both of which he dispensed in generous measures. Clubs where he performed major work were invariably presented with a random selection of Philip and McEwan long-nosed spoons or rut irons.

Having fallen in love with Turnberry in the wake of his dramatic post-war renovation of the Ailsa course, and my involvement as a writer, he was ready, willing and able to answer questions nobody else could. Taking a leaf out of his mentor’s book, he also made models of the greens to aid his machine operators.”