Thomas Patrick Joseph Hennessy was a professor of surgery at Trinity College, Dublin and a former president of the Royal College of Surgeons in Ireland. He was born in Graiguenamanagh, County Kilkenny, Ireland on 19 March 1933, the eldest of two sons. His parents ran a pub and drapery. He attended Knockbeg College and went on to study medicine at University College Dublin, qualifying in 1957. He spent the early part of his surgical training in Dublin and then, in 1961, went to St Catherine’s Hospital in Birkenhead. He later worked at Whiston Hospital in Merseyside, where he gained much experience in general and upper gastrointestinal surgery in a busy service at a time when gastrectomy was the standard treatment for complicated or severe duodenal ulcer. He continued his training at the Royal Southern Hospital and obtained his fellowship of the Royal College of Surgeons in Ireland in 1963 and of the Royal College of Surgeons of England in 1964. In 1964 he was a tutor in surgery at the Mater Hospital in Dublin with Eoin O’Malley, and there developed a lifelong interest in surgery of the oesophagus. During that time, he obtained his MCh degree. After a year in research with Owen Wangensteen in Minneapolis, he returned to Ireland as a lecturer in surgery at Trinity College Dublin in the department of George Fegan. In 1970 he became a consultant surgeon at St Finbarr’s Hospital, Cork and a senior lecturer with Michael Brady in the university department of surgery and, five years later, was appointed as professor of surgery at Trinity College Dublin; he was named regius professor in 1984, a post he held until he retired in 1998. When he was appointed professor and head of department, his duties were formidable. His overall responsibility for the delivery of the surgical teaching programme for the medical students extended to several Dublin hospitals – St James’s, Sir Patrick Dun’s, Mercer’s, Baggot Street, National Children’s Hospital and the Adelaide and Meath hospitals. With the development of a reconfiguration programme, six of these hospitals were closed and transferred to the rapidly expanding St James’s Hospital, which was to become the largest public hospital in the country. The final examinations in surgery were always formidable occasions, not only for candidates but for examiners and those organising details of the clinical and oral components. The examiners’ dinner in the venerable ambience of Trinity was always a convivial occasion, replete with apocryphal surgical stories and enjoyed by all, including the external examiners. Tom’s character reflected a deep concern and dedication to his family, his religion, his patients, his students, his colleagues and his profession. His serious demeanour and measured way of speaking conveyed a gravitas, but underlying this was a personality filled with good humour, a sense of fun and a capacity for friendship. He and his wife Maura hosted many happy social gatherings at their home in Lucan, to which scores of colleagues and young surgeons were invited. They had four children, of whom they were hugely proud and whose achievements Tom would delight in recounting. He transformed the department of surgery in Trinity and established its international reputation as a centre of high quality in the management of oesophageal cancer. Despite restricted physical facilities, he was able to carry out an extensive service in general surgery, supervise and conduct an active teaching programme for medical students, while recording and publishing his surgical experience regularly and consistently in journals of high impact. In so doing he extended the scope of his international contacts and became an invited speaker and external examiner in several hospitals and medical schools. As he developed his specialty interest he was supported by a series of committed and talented lecturers, who in turn went on to be independent contributors to surgical progress in Ireland. Young surgeons from countries in Europe, the United States, the Middle East and China spent periods of time as fellows in his department. His welcoming approach and concern for their welfare ensured enduring links and friendships throughout the international surgical community. His strong support of the prestigious Surgical Research Society resulted in many papers from his department being accepted for presentation. He was the first Irishman to be elected president of the Society. In addition to over 120 scientific publications, he co-authored a highly-recommended a book with Alfred Cuschieri *Surgery of the oesophagus* (Eastbourne, Bailliere Tindall, 1986). He also wrote books on oesophageal reflux and, with his successor John Reynolds, upper gastrointestinal cancer. In 1996 he published a paper in *The New England Journal of Medicine* reporting on a single-centre controlled clinical trial comparing resection alone with primary chemo-radiation treatment for patients with oesophageal carcinoma (‘A comparison of multimodal therapy and surgery for esophageal adenocarcinoma’ *N Engl J Med*. 1996 Aug 15;335[7]:462-7). The results demonstrated much longer survival for patients with adenocarcinoma who had received the multimodal therapy. The paper was both influential and controversial, generating extensive discussion. In his autobiography *My life as a surgeon* (Dublin, A&A Farmar, 2011), Tom commented (I believe with considerable satisfaction) that during a meeting at which the paper was criticised, it transpired that at least half of the critics had not read it! In 1992, he was elected vice president of the Royal College of Surgeons in Ireland. After two years, the vice president automatically succeeds the president. In preparation for the extensive overseas responsibilities of president, Tom, with the help of a psychologist, had to overcome his aversion to flying and went on to become an enthusiastic international traveller. He was an honorary fellow of the Royal College of Surgeons of Edinburgh, the Royal College of Physicians and Surgeons of Glasgow, the College of Surgeons of South Africa and the College of Physicians and Surgeons of Pakistan. He also received the honorary fellowship of the Royal College of Surgeons of England, thus becoming one among very few who have gained the FRCS by both examination and honorary conferment. His last two years as professor at Trinity were extremely difficult, due to ill-health and especially because of the progressive illness of his beloved wife, Maura, who died in March 1998. A new medical school was developed jointly between the Royal College of Surgeons in Ireland and University College Dublin Malaysia and, in July 1998, he took on the position of foundation professor of surgery and dean of the Penang Medical College. In what was for him a new working environment, he demonstrated his considerable administrative skill and placed the fledgling medical school on a sound base. Upon leaving in 2004, he was conferred with the title of ‘Dato’, a high honour of distinction bestowed by the Malaysian government. During his time in Penang, he met Birgitta Buckholt, a Swedish lady who had a career in banking and had been a magistrate in Sweden. They married in 2001 and enjoyed a full and happy life together until Tom’s death on 9 April 2018.