David Furnell worked as a labourer at the Thames Iron Works. He began his football career in 1892 playing for St Luke's, a small club in Beckton. At the time he was a full back or wing half and was eventually appointed captain. Later he was to play for Castle Swifts as a goalkeeper. Furnell joined the Thames Iron Works football club in the 1896-1897 season. He had to wait until the final game before making his debut. He did well against Barking Woodville and held his place throughout most of the 1897-98 season. Furnell played so well that he chosen to represent Essex against Middlesex in November, 1898. However, he was eventually replaced in the team by Bob Heath, a highly-rated goalkeeper who had been playing for another local side, West Ham Garfield.