Jamison made 9-of-14 shots from the floor, including 3-of-6 3-pointers, in three quarters. Caron Butler added 17 points for Washington (2-2), which shot 55 percent.
Gerald Wallace scored 22 points to lead the Bobcats, who dropped to 0-3 in the preseason. He was the only Bobcat to reach double figures.
Charlotte forward Melvin Ely scored 7 points in his first action of the preseason after being sidelined by a left knee strain.
Jamison hit a pair of 3-pointers during an 11-0 run that gave the Wizards a 66-55 lead with 7:18 remaining in the third quarter. The Wizards never trailed after that and built the lead to 16 points several times in the fourth quarter.
The Wizards led 53-47 at halftime after shooting nearly 61 percent from the floor in the first 24 minutes. Jamison scored 16 points on 7-of-11 shooting in the first half.
The game was played early so students and teachers from area schools could attend.