The Gull Lake school board heard passionate pleas on both sides of the issue Monday night before voting to readmit the boy, who's 14.
The boy will reportedly be enrolled in Gateway Academy, an alternative school, but will be banned from other school properties until 2014.
Police said the boy brought a handgun and 200 rounds of ammunition to a middle school in November 2011 as part of a plan to run away with two classmates. The gun was found under rocks in the parking lot.
The Gull Lake district is 15 miles northeast of Kalamazoo.