New York also waived Ryan Arcidiacono.
Reddish, the 10th pick in the 2019 draft, was the victim of an overpopulated Hawks roster of talented young wing players. That ultimately left him without the role or pathway to a contract extension -- and the Hawks made it a priority to move him ahead of the Feb. 10 trade deadline.
Reddish, 22, has averaged career highs in points (11.9), field goal percentage (40%) and free throw percentage (90%) this season. He also is shooting 38% on 3-pointers this season, up from 26% last season.
Reddish also has had two 30-point games -- something he hadn't done in his first two NBA seasons. Reddish gives the Knicks a versatile young wing to grow with their core of talent, including his former Duke teammate RJ Barrett.
Knox was the ninth pick in the 2018 draft, but he has been unable to gain traction in New York.
The first-round pick is the key acquisition for the Hawks, giving general manager Travis Schlenk an increased asset in his arsenal to use in trades as he actively looks to make improvements to a team whose sluggish start comes after a trip to the Eastern Conference finals last season.
Charlotte's first-round pick is protected through the top 18 in 2022, the top 16 in 2023, and the top 14 in 2024 and 2025. It becomes two second-round picks if not conveyed before 2026.