Harris hit 13 of 14 foul shots and the Bulldogs made 22 of 28 from the line.
The Citadel had an 11-point lead with 6 minutes remaining in regulation but scored just five points the rest of the period. The Bulldogs led by six with 2 minutes left in the first OT but only made two free throws after that point. Longwood led by five with 2 minutes left in the second OT but did not add to their score. The Citadel led throughout the final period.
The Lancers were playing their first home game since Nov. 15. They were 1-6 since then.
The Citadel plays at North Carolina State on Sunday. Longwood plays at George Washington on Dec. 28.