[2] During World War I, his methods and inventions for restoring and rehabilitating wounded soldiers laid a foundation for modern physiotherapy practices.

As a child, McKenzie did not regard himself as an athlete, saying, "Looking back with an eye of memory I see a rather delicate child, sensitive at being called pale-faced, a roamer of the woods and fields with a mind filled with romance that Sir Walter Scott and Fenimore Cooper alone could instill, going unwillingly to school, distracted by thoughts of the Deerslayer..."[4] In preparation for McGill he attended Ottawa Collegiate Institute (currently known as Lisgar Collegiate Institute) in 1883 at nearby Ottawa, Ontario.

[6] McKenzie became involved in acrobatics and gymnastics; set a 5-foot, 9-inch high jump record; ran hurdles; boxed; played football; and was on the tug-of-war team.

[8] McKenzie found his athletic abilities focused on sports that did not solely require strength or stamina, but rather skill, coordination, and practice.

[11] After graduating, McKenzie gained experience as a physician and surgeon, developed his own medical practice and became an anatomy instructor at McGill.

[3] During the 1890s, McKenzie asked McGill to develop a department and school of physical education, but the university declined, citing lack of money.

[19] His research led to an article, "The Facial Expression of Violent Effort, Breathlessness and Fatigue," published around 1900 in the Journal of Anatomy and Physiology in London.

Eager to volunteer his services as a physician and surgeon, McKenzie chose instead to enlist with the Royal Army Medical Corps after encountering some red tape and delays in his paperwork.

[31] He also spent a large portion of his time helping plastic surgeon Dr. William L. Clark rehabilitate those whose faces had been disfigured by war.

[33] The property had long since become abandoned; however, it was situated in a picturesque setting, making a perfect retirement home that would kindle McKenzie's artistic imagination.

Being a man who could never sit still for very long, a typical summer's day would find him working in his studio, walking in the woods, swimming, canoeing, going into town or giving presentations to local groups.

[36] His spirit refused to allow him to slow down, despite warnings from his physician about his deteriorating heart, and consequently, McKenzie collapsed suddenly and died on April 28, 1938.

[23][37] R. Tait McKenzie's influence was so strong in the fields of physical education, medicine, the arts, and the military that hundreds of people expressed sadness and felt personal loss in his passing, many sending condolences to his widow, Ethel.

Near the end of his life, McKenzie said he wanted his heart to be buried in front of the Scottish-American War Memorial that he had created in Edinburgh, Scotland.