Born at Limerick; entered the medical service of the Navy in 1838. He was Assistant Surgeon on board the *Zebra* at the siege and capture of St Jean d'Acre, after which he visited the Holy Land, and at Jerusalem was created a Knight of the Holy Sepulchre, being invested with the sword and spurs of Godfrey de Bouillon. He served later on the North American and West Indian stations, and, after promotion to Surgeon, on the coast of Africa, where he was so successful in the management of an outbreak of fever that the crew of the ship presented him with a cocked hat, sword, and epaulettes in token of their esteem. He served on shore with the Royal Marines during the Crimean War and was awarded the Medal with two Clasps, Balaclava and Sebastopol, and the Sultan's Medal. He was also made a Knight of the French Legion of Honour. Finally he served for three years as Surgeon of the Receiving Ship at Greenwich and was promoted to be Staff Surgeon. Walsh retired in April, 1870, and died in his native town, Limerick, in 1873, of suppurative otitis media with intracranial complications.