Lawless, William (c.1764–1824), surgeon, United Irishman, and officer in Napoleon's Irish Legion, was born in Dublin, son of John Lawless and Mary Lawless (née Beauman) of Shankill, Co. Dublin. He was a distant relation of Valentine Browne Lawless (qv), 2nd Baron Cloncurry, a prominent United Irishman. Apprenticed to a Dublin surgeon, Michael Keogh of Meath St., in March 1781, he obtained letters testimonial from the RCSI in June 1788, and in October 1789 was appointed a superintendent of dissections at the college's surgical school in Mercer St. Elected a member of the college in March 1790, he established his own practice in Meath St. In September 1794 he was appointed professor of anatomy and physiology at the RCSI and later collaborated with William Hartigan (qv) to publish The syllabus of lectures in anatomy and physiology, delivered in the schools of anatomy and surgery, under the direction of the Royal College of Surgeons in Ireland (1796). The work was well received and Lawless, recognised as a surgeon of considerable skill, was elected MRIA. He numbered Abraham Colles (qv) among his students and, an amateur poet, he was an associate of Thomas Moore (qv).
Lawless was also a committed member of the United Irishmen and was a close friend of both Lord Edward Fitzgerald (qv) and John Sheares (qv). After the failed rebellion of 1798, he was warned that there was a warrant out for his arrest and he spent a period in Dublin avoiding Maj. Henry Charles Sirr (qv) and his agents before fleeing to France. In his absence, his name was removed from the members' list of the RCSI (November 1798) and he was finally expelled from the college in February 1799; he was also deprived of membership of the RIA. He became a prominent member of the Irish émigré community in Paris and associated with Thomas Addis Emmet (qv) and Arthur O'Connor (qv) after their arrival in Paris in 1802. In 1799 he served as a volunteer officer on the staff of Gen. Brune during the campaign against the British expeditionary force in Holland and was given a temporary commission as a chef de bataillon. After the Irish Legion was formed in August 1803, he was commissioned (December 1803) with the rank of captain, moving to Brittany with the legion for an intensive period of training. After the failure of the rebellion of Robert Emmet (qv), the different factions in the Irish Legion engaged in a series of disputes, resulting in much ill-discipline. Lawless was associated with the Emmet faction and when the new commander, Chef de bataillon Antoine Petrezzoli, reorganised the legion, Lawless was detached on staff duty to Brest (1808).
In 1809 he rejoined the 1st Battalion and was prominent in the defence of Flushing during the Walcheren campaign. Badly wounded by a musket ball, which entered under his right eye and lodged under his ear, he was in the house of his friend, Dr Moke, having his wound treated when Flushing fell to the British on 15 August. In this way he avoided capture and made his way to Paris, saving the regimental eagle. He was received by Napoleon and, promoted to major, was awarded the Légion d'honneur. Appointed to command the depot of the 1st Battalion at Landau, he oversaw a reorganisation of the unit, recruiting men from the prisoner-of-war camps in France. After constantly writing letters to the ministry of war to request weapons and equipment, he was promoted (February 1812) to colonel and given command of the regiment. In 1813 he took part in the campaign in Silesia, the Irish battalions being decimated in the action at the Boder river on 19 August. On 21 August he led his troops again at the battle of Löwenberg, where he was seriously wounded when his leg was shattered by a canon ball. He was carried to the rear on a door and although Napoleon ordered his personal surgeon, Baron Dominique Jean Larrey, to operate, the leg could not be saved and had to be amputated.
After a period of convalescence at Leipzig, he returned to Paris and it was announced that he was to be promoted to the rank of general of brigade as a reward for his service. Napoleon's abdication in April 1814 prevented this promotion. After the restoration of the Bourbon monarchy, he remained in France and was one of the Irish officers who protested against the plans of the new administration to transfer funds from the Irish College in Paris to Maynooth College. Due to his disability, he took no part in the Hundred Days campaign (March–June 1815) and spent the rest of his life in quiet retirement at Tours. He died in Paris on 25 December 1824 and was buried in the Père-Lachaise cemetery.
He married (date unknown) a Miss Evans, daughter of Hampden Evans (1740–1820), a wealthy United Irishman, of Portrane, Co. Dublin. They had children and Mrs Lawless was, by all accounts, a woman of considerable intelligence and character. After Lawless's death she asked Miles Byrne (qv) to buy two graves in the Père-Lachaise cemetery: one for her husband, the other for herself. She died in Paris in August 1854 and was buried beside her husband.
There is a considerable collection of William Lawless's papers in the Service Historique de l'État-Major de l'Armée at the Château de Vincennes. These include reports on the defence of Flushing and also on the organisation of the Irish Legion. His account of the defence of Flushing was published by John G. Gallaher in the Irish Sword in 1989. There is also a small collection of his papers in the archives of the Ministère des Affaires Etrangères in Paris.