The deals were announced Tuesday. Both players reached agreements before the league's signing moratorium ended last week.
Dunleavy, who turns 35 in September, got a three-year, $14 million contract. He averaged 9.4 points in 63 games - all starts - and shot 41 percent from 3-point range for Chicago last season. In the playoffs, he averaged 10.9 points and shot 48 percent from beyond the arc.
The 30-year-old Brooks averaged 11.6 points for the Bulls last season.
Chicago's roster returns virtually intact after a 50-win season that ended with a loss to Cleveland in the Eastern Conference semifinals. The Bulls fired coach Tom Thibodeau and replaced him with Fred Hoiberg.