On 19 September 1899, he was promoted to lieutenant-colonel and assumed command of the 7th Dragoon Guards. The regiment embarked the SS Armenian in Southampton on 8 February 1900, and departed for service in South Africa, with Lowe in command of the men on the ship. From 1900 to 1902, he led the regiment in the Second Boer War, being present at the capture of Pretoria and the Battle of Diamond Hill, and was promoted brevet colonel in November 1900. Lord Kitchener's despatch of 8 August 1901 related how "at midnight on the 30th July Colonel Lowe, 7th Dragoon Guards, successfully surprised a farmhouse, from which he took 11 armed prisoners with rifles, bandoliers and horses." Lowe was twice more Mentioned in Despatches: in Lord Roberts' Recommendations, 2 April 1901 and in Lord Kitchener's Final Despatch, 23 June 1902. He received both the Queen's and King's South Africa Medal. Following the end of the war in June 1902 he returned home on the SS Galeka which arrived in Southampton in October 1902. He left the 7th Dragoon Guards in March 1903 to become Assistant Quartermaster-General of the II Corps, being promoted to full colonel. In May 1905, he went to the Northern Command as colonel in charge of cavalry records and staff officer for the Imperial Yeomanry. He was made a Companion of the Order of the Bath in 1906. He went on half-pay in March 1907 and retired a year later.
On the outbreak of the First World War in 1914, Lowe rejoined the army as Inspector of Cavalry, and was appointed as a Brigade Commander with rank of Brigadier-General in 1915. He was commander of the 3rd Reserve Cavalry Brigade, stationed at the Curragh Camp, at the outbreak of the Easter Rising on Monday, 24 April 1916. On being informed of the Rising by phone, he ordered the brigade to Dublin by train. Arriving himself at Kingsbridge railway station in the early hours of Tuesday morning, Lowe assumed command of British forces in Dublin and set about securing the line between the station, Dublin Castle and Trinity College, thus dividing the rebel positions north and south of the river. It was Lowe who ordered the shelling of Liberty Hall by field guns from Trinity College, and who ordered the Sherwood Foresters to continue advancing on Mount Street Bridge with a high cost in casualties. On Saturday, 29 April, after being approached by Nurse Elizabeth O'Farrell, he agreed to negotiate with the leaders only if they would surrender unconditionally, and at 2.30 pm that day, accompanied by Nurse O'Farrell, Patrick Pearse surrendered to Lowe. He was awarded the honorary rank of major-general when he finally retired in March 1919.
Personal life
Lowe married, in 1895, Frances Broster, the widow of Captain Robert Harry Johnson of the 64th Foot Regiment and daughter of Francisco de Salvo, of Salerno, Sicily. They had a son, and a daughter Elizabeth, who became a nun. Their son, John, was a British Army officer who with his father also took part in the suppression of the Rising and accepting the surrender of Pearse —fought at Gallipoli and the Somme and subsequently became a Hollywood actor under the screen name John Loder. General Lowe died in London on 7 February 1944, aged 82. Neither an otherwise comprehensive obituary in The Times nor an entry in Who Was Who 1941–1950 made reference to his role in the Easter Rising, although it is mentioned in John Loder's autobiography, and there is a photograph of Pearse surrendering to him.