The football star, who had been based in the US in recent years, died aged just 49.
In a statement the club added: ” We are deeply saddened at the passing of our former player Chris Bart-Williams.”
It came the same day Nottingham Forest star and England legend Trevor Francis died aged 69.
Francis also played for Sheffield Wednesday, with the team playing tribute to both stars.
Bart-Williams, who was known by the nickname Bartman, had poured more than three decades of his life into football, both as a player and coach.
It was a life dedicated to the game which he started building foundations for as a mere 16-year-old.
The midfielder scored Forest’s last goal in the Premier League with his 76th-minute winner against Leicester, and he would remain at the City Ground until 2002.
After retiring in 2006 he moved to the United States and helped coach their successful women’s national team. Aged 47, he last year worked in US academy football.
Bart-Williams was just 16 when he earned a spot in the Leyton Orient first-team.
His talent was quickly recognised, and the teen was shifted up to Sheffield Wednesday.
The Owls shelled out £275,000 to bring him to Hillsborough in 1991, the year they were promoted to the English top flight, the First Division, as it was then known.
The Sierra Leone-born man played 124 times for Wednesday, scoring 16 goals – including a hat-trick against Southampton.
In 1995, Bart-Williams joined Nottingham Forest in a £2.5million move. He turned out more than 200 times for Forest, finding the net 30 times, despite playing several games at sweeper.
He left in 2001 to join Charlton after the City Ground club found themselves in financial trouble.
Bart-Williams played for Ipswich for a short period before he jetted to Cyprus.
He played a handful of games at Marsaxlokk before hanging up his boots – until he met American coach Tony DiCicco.
Under the legendary guidance of Dicocco he lead two women’s teams.
After almost more than five years in Connecticut, the coach admitted he was exhausted.
Speaking to The Mirror, Bart-Williams said: “I was burned out. I needed to take a break for three or four years to recuperate.
“I’d spent a such a large portion of my life – since I was 16 – in the professional game and then had six or seven years coaching in Connecticut. I was done.”
But, he quickly started his own business working with youngsters, which he admitted he was loving in 2018.
Speaking from his home in Charlotte, North Carolina at the time, Bart-Williams said he could see himself staying in the states for the rest of his time.
He said: “It’s very different. I don’t miss the English weather, that’s for sure!
“I miss the people, the banter, the fierce sarcasm, a good old cup of English tea, an English breakfast and the cultural environment, but Americans are very generous people, they really are.”
Bart-Williams added: “I do miss England at times, but we have a nice life over here, we really do.”