It was almost 11 p.m., and Emelia Holden was finishing up her shift as a server at a Savannah, Ga., pizzeria when she felt a hand on her backside.

She reacted immediately, yanking the man backward by his red shirt as he tried to walk away and wrapping her arm around his neck before using her body weight — all 115 pounds of it — to slam him to the ground, knocking his white sunglasses askew.

“You don’t touch me,” she yelled, adding expletives as he sat against a trash can, stunned.

The June 30 encounter was captured on a surveillance video that has been viewed more than four million times since her cousin shared it online.

Ms. Holden, 21, of Savannah, said in an interview on Sunday that the episode led people to reach out, including women who told her they had showed the video to their daughters. Other servers shared their stories of being harassed or assaulted, she said, and told her watching the video had empowered them to react more assertively next time.