The US actor died “suddenly” on Friday morning, his publicist Mia Hansen said, attributing his death to natural causes.
His death was first reported by celebrity website TMZ.com.
Reddick, a character actor, played impassive hotel concierge Charon in all four of the John Wick films, starring Keanu Reeves, the last of which is due for UK release next week.
He also played Cedric Daniels in the popular HBO drama, appearing in all 60 episodes alongside stars including Dominic West, Idris Elba, Michael K Williams and Wendell Pierce.
Pierce described the actor as “a man of great strength and grace”, and said his death was “sudden, unexpected, sharp, painful grief for our artistic family”.
“As talented a musician as he was an actor. The epitome of class,” he tweeted, alongside a picture of Reddick.
“An sudden unexpected sharp painful grief for our artistic family. An unimaginable suffering for his personal family and loved ones.
“Godspeed my friend. You made your mark here. RIP.”
The actor began his screen career in the mid-1990s, with guest roles on series including The Nanny and New York Undercover, going on to big-screen roles in Great Expectations and The Siege.
He later landed the part of Cedric Daniels in the popular HBO drama The Wire, appearing in all 60 episodes.
Reddick was also known for his work on television show Fringe, Bosch and Lost.
He also lent his voice to animated shows including Adult Swim’s Rick And Morty.