Dan Leno was born George Wild Galvin in London, one of the many children of performers John and Louisa Galvin. After his father’s death, his mother married a comedian of Irish decent known by the stage name of Leno. George started performing at very young age, at first with his parents and elder brother; and later with his mother and step-father, as Dan Patrick, famously known for his clog dancing.
By 1888 George returned to the London stage, soon becoming one of the star comedians of the Victorian Music Hall. Now, as Dan Leno, George fazed-out dancing in favour of ludicrous presentations of common characters and by the age of 41 was billed as “the funniest man on earth”.
Off stage, however, George’s erratic behaviour and heavy drinking soon proved the need for treatment in a mental home and Leno died shortly after this aged forty-three. His cause of death is today considered to have been tertiary syphilis.
George Wild Galvin married Sarah Reynold, known as Lydia, in 1884. They had six children.
See ODNB http://www.oxforddnb.com/view/article/34497?docPos=1