David Watts was born on 14 March 1886 in Maesteg, Wales.  Born into a family of miners, he began working in a coal mine at the age of 14 after leaving school. He took a keen interest in rugby, playing in his spare time. He honed his rugby skills with Aberaman Cynon Stars Junior Rugby Club and Rhymney RFC, before joining Maesteg RFC.

There he built up a solid reputation as a lock and helped his hometown win the Glamorgan Challenge Cup in 1912. This victory enabled him to take his career to the next level, and he was selected to play against England – the reigning Grand Slam champions – at Twickenham, on 17 January 1914.

Wales lost the first match but won the last three of the tournament. Of all Watts' matches, the most memorable was the final against Ireland at the Balmoral Showgrounds on 14 March 1914.

Excessively violent, this match went down in the annals of rugby history as the most brutal ever played, and the Welsh pack, of which Watts was a member, acquired the nickname of the "Terrible Eight" from the newspapers. Watts played one last game for his country in an exhibition match against the Barbarians in 1915. Led again by Alban Davies, Watts took part in this match designed to boost recruitment for the Welsh Guards, although it was not recognized as a fully-fledged international match.

He continued to play rugby when the First World War broke out, but in June 1915 he enlisted for active service and was posted to the 7th Battalion King's Shropshire Light Infantry. He arrived at Boulogne in October 1915 and was sent to fight in the Battle of Ypres.

His regiment was then sent to the Somme. Two Welsh rugby internationals had already been killed in the offensive to capture Mametz Wood the previous week - Dick Thomas and Johnnie Williams. 

He was promoted to Corporal on 1st July 1916 and just a few days later, on the 14th, David Watts was killed during the assault on Bazentin Ridge.

He has no known grave and is remembered on the Thiepval Memorial (Pier and Face 12A and 12D).