He took his degree of Doctor of Medicine at St.Andrews in 1696; found use for mathematics in his studies of medicine; became a Fellow of the Royal Society; and being by chance at Epsom when Queen Anne's husband was taken ill, prescribed for him so successfully that he was made in 1705 Physician Extraordinary, and upon the occurrence of a vacancy in 1709 Physician in Ordinary, to the Queen.

Swift calls him her favourite physician.

In 1710 he was admitted Fellow of the Royal College of Physicians.

That was Arbuthnot's position in 1712-13 when, at the age of forty-five, he wrote this "History of John Bull." He was personal friend of the Ministers whose policy he supported, and especially of Harley, Earl of Oxford, the Sir Roger of the History.
After Queen Anne's death, and the coming of the Whigs to power, Arbuthnot lost his office at Court.

But he was the friend and physician of all the wits; himself without literary ambition, allowing friends to make what alterations they pleased in pieces that he wrote, or his children to make kites of them.