Dr Séamus Mac Suibhne (Sweeney) (1978-2019) was a widely admired psychiatrist, writer and scholar whose contributions ranged from psychiatric care to Greek philosophy, and from medical education to the application of new technologies in educational and clinical settings. Séamus wrote extensively on these and many other themes in the professional and popular literature. In his clinical work, Séamus was a compassionate doctor, effective team-worker and skilled manager. He served as a representative of graduates on the Governing Authority of University College Dublin (2008-2013), secretary (2007-2009) and then president (2009-2014) of the Psychiatry Section of the Royal Academy of Medicine in Ireland, associate editor of the Irish Journal of Medical Science (2012-2019) and a member of the HSE National Shared Record Project. Séamus continuously wrote essays, book reviews, blogs and short stories, and won the 2010 Molly Keane Writing Prize. Philosophy was, perhaps, his greatest intellectual passion and he spoke and wrote extensively on themes linking philosophy with clinical care, the history of psychiatry and reflective practice in medicine. Séamus wrote and co-wrote on a range of other topics including psychiatric liaison with primary care, 'vampirism' as a mental illness, translation and interpretation in psychiatry, synaesthesia, 'new' mental illnesses such as solastalgia and hubris syndrome, bibliotherapy, the work of Nicholas Culpeper (a seventeenth-century English physician) and mental illness among psychiatrists. Séamus Mac Suibhne is deeply missed in Irish psychiatry, but his many contributions bear elegant, lasting testament to a dedicated family man, a gifted doctor and an enquiring, often brilliant mind.