Lees was elected to the House of Commons for Oldham in 1886, a seat he held until 1892, and later represented Birkenhead from 1894 to 1906.
He volunteered for active service during the Second Boer War, and on 24 February 1900 was appointed a captain of the 26th (Dorsetshire) Company serving in the 7th Battalion, Imperial Yeomanry,[3][4][5] which left England for South Africa on the SS Manchester Merchant in early March.
[6] He was mentioned in despatches and awarded the Distinguished Service Order (DSO) in November 1900.
[7] After his return to the United Kingdom he was appointed a supernumerary major of the regiment in January 1902.
He died in October 1908, aged 47, and was succeeded in the baronetcy by his eldest son Thomas.