Born in Finchley, England and raised in Sussex Weald, Stirling attended Bishop's Stortford College and the University of London.

Although having encouragement by his family and even a natural curiosity, the choice for the medical career was only taken in his last year at the Bishop's Stortford College, where his Headmaster received the news as a "startling new development".

He deemed himself "very, very lucky"[2] for he got all the House Appointments he wanted and, hence, completed 3,5 years of his early career as a junior staff at the London Hospital.

He then worked as Outpatient Surgical Officer at a nearby hospital from his private practice for a brief time, when he finally decided to "continue the upward climb on the ladder of specialization".

It was 14 January 1935, when Leader Stirling received a letter from the Universities' Mission to Central Africa (UMCA), asking, "A doctor is urgently needed at Masasi.

[7] The Masasi Mission Hospital was "in a primitive state"[2] according to Dr. Stirling, the structure being a thatched hut of rammed earth with no running water.

Since the initial installations were not enough, in 1946 Leader Stirling added four new wards, store-rooms and nurses' and dressers' rooms, "completing his plan for the main block, including the hospital chapel.".

Leader Stirling also established and maintained a chain of 20 dispensaries to fill the lack of medical infrastructure in the region comprehending "almost to the coast and right down to the Mozambique border, the furthest a hundred miles from Lulindi".

In his first visit in 1940 he was invited to discuss the brink of an epidemic of malaria, brought by troops during World War II and unknown to Nairobi until then given it sits 5,500 feet above ocean level.

And not only for his medical work, for he had also done a great deal of building and done very much to strengthen and establish over a wide area the Scout movement which was providing itself an asset of ever-increasing value in the diocese.".

This meant he could dedicate himself more to the medical work which, in 1958, he describes as follows I had been working single-handed for nearly 24 years, and now had to deal with eighty beds always full, several hundred outpatients daily, a weekly leprosy clinic of 400, teaching and administration of a nursing school and its hostel, general administration of the hospital, visiting a dozen remote dispensaries, and performing up to twenty operations per week.

Leader Stirling departed Mnero to Dar es Salaam and met the Bishop of Moshi who appointed him to a position in Kibosho, at the slopes of the Kilimanjaro where he was supposed to start a new hospital.

In 1973, following his ever-increasing political involvement, he was placed on a Presidential Commission moved to Dar es Salaam, then capital of the country.

If you have been doctoring in an area for twenty years and more, you are bound to come to share your patients' interests, to understand their troubles, and to join hands in trying to overcome their difficulties."

His political career might have come to a halt if it wasn't for the fact that the University of Dar es Salaam appointed him to run for a National Seat.

[2] Another position he held was chairman of a Commission to investigate the National Provident Fund, early Tanzania's social security program.

What comfort, Sir, is a fine Hospital (in) Dar es Salaam to the people who are dying out in the bush, twenty, thirty, forty, even fifty and more miles from the nearest doctor?

[2] Indeed, while Minister, Leader Stirling started the Tanzania National Tuberculosis and Leprosy Program,[2] unifying the scheme of treatment and extending it to the whole country.

Leader Stirling attended to the International Conference on Primary Health Care in Almaty (former Alma-Ata) from which originated the Alma Ata Declaration.

Eventually, he developed his unique modus operandi which he describes as: The hospital was open 24 hours a day and there was always someone to receive a patient, even in the middle of the night.

The nurses of course came on and off in shifts, but the doctor and the medical assistants had to be more elastic, and their daily programme was subject to all manner of unexpected variations both inside and outside the hospital.

Trauma surgeries were very common to repair blade wounds, in cases of violent attack or "not from fighting but from carelessness",[2] since local culture would allow children to play with knives and people had the custom to carry those weapons on top of their loincloths.

[2] Besides those cases, beast attacks were a recurrent happening, with crocodiles, "lion, leopards, hippopotamus, wild boar, buffalo, baboon, hyena, and even the little bushbuck.

Plastic surgeries were frequent for chronic ulcers, burns, hare-lip, vesico-vaginal fistula, trachoma, various scars and most importantly elephantiasis, to which he devised a new bloodless operation.

He was also able to align local customs with modern medical norms in the case of circumcision surgeries, which were performed by untrained tribal leaders with little to no antiseptic precautions before his intervention.

Examples of those are malaria (the most common),[2] yaws, bilharzia, hookworm infestation, leprosy, and ulcers of the leg (acute or chronic) "the biggest constant problem".

Kibosho had more worms, stomach trouble, high blood pressure and rheumatic fever while having less of bilharzia and leprosy relative to the south villages of Lulindi and Mnero.

The challenge to training nurses was that local school heads would hold onto their brightest students, encouraging them to go into teacher-training, under the impression that teaching was the only honourable occupation for an African woman.

Miss May Bell and Leader Stirling's syllabus, based on the British model, was later adopted by the government and implemented all over the country's nursing schools.

[11] He attended to the great Jubilee Jamboree of Scouting at Sutton Coldfield, England in 1957 with a group of 30 Tanzanians (Tanganyikans and Zanzibaris alike) where he met Queen Elizabeth II.