18 year old French / Irish midfielder William Hondermarck joined Norwich on 22nd January 2019 from Irish side Drogheda. He had attracted interest from a number of British clubs after an impressive debut season at Airtricity League first division side Drogheda United and had been linked with Dundee United and Brentford. He was born in France but raised in Ireland. He will begin playing with Norwich's Under-23s (making his debut in a 1-1 draw with Leicester) and Under-18s (making his debut in the 3-0 defeat to Preston in the FA Youth Cup).

Hondermarck was on the bench for Norwich in the Carabao (League) Cup first round clash at Luton on 5th September 2020 which Norwich lost 3-1. The Canaries had 15 first teamers missing due to international call-ups with a further two injured. However he was not utilised. Three days later he scored as Norwich's Under-23s defeated Plymouth 3-2 at Home Park in the Football League Trophy

On 6th January 2021 he joined Harrogate Town on loan until the end of the 2020/21 season. He made his debut on 9th January 2021 coming on as substitute in a 2-1 League Two defeat to Cambridge (featuring another Irish Canary - Wes Hoolahan). He made 3 appearances in total for Harrogate.

He was one of seven players released by the Canaries on 27th May 2021. He joined Notts County on trial in July 2021 playing for them in a 2-0 friendly win over Coalville Town on Saturday 17th July 2021. He then trained with Barnsley's under-23s recently and has signed a contract with the Championship side. He said "I’m very pleased to have signed here. I was very excited to come here with the set-up like this where the first team is so successful for young players, so I’m very pleased to get a chance at this club. I want to help the under 23s as much as possible and then break into the first team; that’s my aim – to make a name for myself.”

Barnsley were relegated from the Championship on 22nd April 2022. Hondermarck made 10 appearances.

He transferred to Northampton Town on 26th January 2023 having only made one appearance for Barnsley during the 2022/23 season. He signed a two-and-a-half-year contract with Northampton.

On 9th June 2023 he was called up to the Congo senior squad for the African Cup of Nations qualifier against Mali. He is eligible to represent Congo through his mother, who is of Congolese descent.