Johnson connected on 13-of-19 from the floor and Josh Smith contributed 17 points and 14 boards for the Hawks, who strengthened their hold on the Eastern Conference's fifth playoff seed.
Atlanta got 16 points from Marvin Williams and 15 from Al Horford while shooting a season-high 63 percent from the field.
Andrew Bogut ended with 21 points and 13 rebounds for Milwaukee, which set a franchise record Sunday for the fewest points scored in a game against the Celtics in an 87-56 loss to Boston.
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