|Full name||William Jonas|
|Date of birth||1890|
|Place of birth||Blyth, Northumberland, England|
|Date of death||27 July 1916 (aged 26)|
|Height||5 ft 8 in (1.73 m)|
|Playing position||Midfielder, forward|
|* Senior club appearances and goals counted for the domestic league only.
† Appearances (Goals).
Starting his career with Jarrow Croft, Jonas scored twice in a Gateshead Charity Cup Final and turned down an offer from Barnsley before moving to Havanna Rovers in 1910. He scored 68 goals in his two seasons there, and moved to Clapton Orient in June 1912 on advice from his friend and fellow Orient player Richard McFadden.
At Orient, Jonas could play in almost any position, even making several appearances in goal. He was sent off during a match at Millwall in January 1915 for fighting with the home goalkeeper Joseph Orme, an incident which started a riot among the 16,900 crowd that had to be quelled by police on horseback.
William was very popular with the female supporters at Clapton Orient – so much so that he was getting a bags of fan mail from the ladies by the week. Things got so bad that he had to put an official request in the Orient programme for the letters to cease as he was very happily married to his dear wife Mary Jane.
At the outbreak of World War I professional football was suspended and Jonas joined the 17th Middlesex Regiment, the "Footballers' Battalion". During the Battle of the Somme, Jonas became trapped in a trench with his Orient team-mate McFadden while fighting at Delville Wood. Under heavy fire, he said goodbye to McFadden, jumped out of the trench and was killed instantly. Having no known grave at the war's end, he was commemorated on the Commonwealth Thiepval Memorial.
- Neilson Kaufman, "The Men Who Made Leyton Orient Football Club", Tempus, 2002, pp. 262.
- Neilson Kaufman & Alan Ravenhill, "Leyton Orient: The Complete Record", Breedon Books, 2006, pp.224.
- Stephen Jenkins, "They Took the Lead", DDP, 2005, pp.52.
-  CWGC Casualty record.