He was famous for his role as Chief Medical Officer of Guinness Brewery, during which time he founded both St James's Gate F.C.
[citation needed] Lumsden was a physician on the staff of Mercer's Hospital in Dublin and in 1902 was the Principal Medical Officer for the Commissioners of Irish Lights.
[6] After the Great Irish Famine (1845–1846) many people moved from rural areas of Ireland into cities such as Dublin looking for food and work.
The classes became so popular that they later became the first registered division of the St. John Ambulance Brigade of Ireland, which Lumsden founded in 1903 and became the first Commissioner, a post he held until his death.
[9] The brigade was involved with many major events in Irish history, including treating casualties from the clashes during the General Strike of 1913 (sometimes referred to as the Dublin Lockout).
During the fighting in the streets of Dublin, Lumsden became a familiar figure as he dashed out carrying a white flag and his medical kit to tend to the wounded on both sides.
He also celebrated his work at the St John Ambulance Brigade by building a Maltese cross sundial at Earlscliffe, which gave him "enormous pleasure".