He was the youngest child of William Archer Kennedy, who worked in the linen trade, and Hessie (Hester) Dill; she was the daughter of Robert Foster Dill, Professor of Midwifery at Queen’s College (later Queen’s University), Belfast, and Belfast City Coroner. This meant young Robert came on his mother’s side from a distinguished family, which included Sir Samuel Dill, Professor of Greek at Queen’s, and Field Marshal Sir John Dill, wartime Chief of the Imperial General Staff. When Robert was a child, the Kennedy family lived for a time at Czestochowa, Poland, taken there by William’s business activity, though when Hessie died, only 34 years old, William Kennedy remained in Poland but sent his children back to Ulster. Robert was installed with his (maternal) grandfather and his two daughters in Fisherwick Place, Belfast. On Professor Dill’s death in 1893, the rest of his household moved to Bangor.
Robert was a boarder at Royal School, Dungannon, from 1984-1893. It is likely that this school was selected as its headmaster at the time was an uncle, also Robert Foster Dill, who had been headmaster since 1892. (He later was Headmaster of Foyle and Londonderry College, closer to family roots.) In 1901 he entered Queen’s College and graduated there (Royal University of Ireland; Queen’s was not an independent university until 1908). He had already made up his mind to specialise in neurology, and quickly obtained a post as a resident medical officer at the National Hospital for the Paralysed and Epileptic in London (later the National Hospital for Nervous Diseases). Already interested in cerebral tumours, especially frontal lobe tumours which can seriously affect, even completely obstruct the eyesight, he was continuously looking for a suitable position in neurology, and despite some distinguished backers, was unable to find one domestically, so in 1910 accepted an invitation to take up a post at the recently-founded Neurological Institute in New York, an 82-bed establishment and the first of its kind in the United States.
After a year in New York he published his seminal article on what later became the Foster Kennedy Syndrome. It was entitled “Retrobulbar neuritis as an exact diagnostic sign of certain tumours and abscesses in the frontal lobes” and appeared in the American Journal of Medical Science in the autumn of 1911.
His reputation flourishing, war broke out in Europe in 1914 he returned home, with his wife Isabel, having volunteered for six months with the Royal Army Medical Service. One of his principal activities was the establishment of hospital for French soldiers at Rig-Orangis, near Paris (his wife worked in the kitchen). He went back to New York in late 1915, but was in Europe again the following year, initially as a general surgeon at a field hospital near the front lines, then with the Harvard Surgical Unit near Boulogne as a neurologist. This time his wife was not with him. One special interest he had was in “shell shock”, which the General Staff notoriously did not recognise, but for Kennedy it was all too real and he interpreted it as arising from the clash for the individual between loyalty, morale and preparedness to self-sacrifice, with, on the other hand, the instinct for self-preservation. Kennedy described later how what he witnessed, destroyed what religious faith he had.
In December 1918 he returned to New York, with a higher position, that of Professor of Neurology at Cornell and head of the neurological service at Bellevue Hospital. This institution, founded in 1736, was the oldest public hospital in the United States. For the next two decades he had a notably successful career and many of his patients originated from the higher (or highest) social strata. He even treated Winston Churchill following the latter’s collision with a taxi (as a pedestrian); they corresponded thereafter. Churchill telephoned him in 1941, enquiring of Kennedy if he thought the United States would remain neutral in the Second World War, or not. An even more distinguished patient was the US President, Franklin D Roosevelt. Kennedy did, however, suffer considerable financial losses following the 1929 crash.
In 1938 he separated from his wife and subsequently they divorced. The following year he fell badly ill, with a huge haemorrhage from a nasal artery which proved extremely hard to treat and which curtailed his professional and other activities. But it did not prevent him remarrying, which he did in 1940, to Katherine Caragol y San Abria. In 1951 he became seriously ill with polyarteritis nodosa (a rare but serious blood vessel disease in which small and medium-sized arteries become swollen and damaged). He was taken at his own request to his old ward at Bellevue, where he died.
His many honours and distinctions included the Military Cross, his appointment as a Chevalier de la Légion d’honneur, an honorary DSc from Queen’s University, Belfast, and election as a Fellow of the Royal Society, Edinburgh. He is believed to be the only graduate of Queen’s University, Belfast to be the sole eponym for a known condition, illness or syndrome.