Harry Potter was drawn to Cho's good looks and developed a crush on her when she was in her fourth year, and asked her to the Yule Ball in the next, though she had already agreed to attend with Cedric. Still, Cho treated Harry kindly, such as in refusing to wear a Potter Stinks badge during the Triwizard Tournament.
In her sixth year, Cho began to return Harry’s feelings, though she felt somewhat guilty for doing so, considering the recent murder of Cedric Diggory. She joined Dumbledore's Army and became nervous whenever Harry was nearby. They shared a kiss under the mistletoe around Christmas, but this was spoiled by Cho beginning to cry, and Harry being at a loss for how to respond.
The two went on a date in Hogsmeade on Valentine's Day, but Cho’s feelings for Harry were confused because of her continuing grief over Cedric’s death and Harry’s discomfort with discussing it. She also became jealous of Harry’s friendship with Hermione Granger, and in a moment of weakness and insecurity, ditched the date. Harry, who was inexperienced with girls, found Cho’s behaviour very confusing, especially when she tried to make him jealous and to gauge his feelings for her by mentioning that Roger Davies had asked her out. Thus, their relationship was already strained when Marietta Edgecombe betrayed the D.A. and Cho stood up for her, angering Harry. After that, their relationship simply “fell apart”.
When Cho saw Harry on the Hogwarts Express in 1996, she avoided him, and Harry reflected that they were too embarrassed to even look at each other, let alone talk to each other. However, by 1998, any negative feelings on Cho's part seemed to have vanished, as she offered to escort Harry to Ravenclaw Tower just before the Battle of Hogwarts. She was disappointed when Ginny Weasley fiercely suggested that Luna Lovegood escort him instead, suggesting that Cho may still have had some feelings for Harry or simply wanted to resolve any of their lingering issues so that they could be friendly again.
Cho remained loyal to her school and to the D.A., returning after she had graduated to participate in the Battle of Hogwarts. She survived the war and eventually married a Muggle.