"- and Katie Bell of Gryffindor dodges Pucey, ducks Montague, nice swerve, Katie, and she throws to Johnson, Angelina Johnson takes the Quaffle, she's past Warrington, she's heading for goal, come on now, Angelina - GRYFFINDOR SCORE!"
-- Lee Jordan commentating on a Quidditch match (OP19)
Katie is in her second year, just twelve years old, when she joins the team as a Chaser (PS11). She is a great addition to the team, earning high praise from Oliver Wood at the beginning of her third year:
“But we also know we’ve got the best-ruddy-team-in-the-school,” he said, punching a fist into his other hand, the old manic glint back in his eye. “We’ve got three superb Chasers.”
Wood pointed at Alicia Spinner, Angelina Johnson, and Katie Bell (CS7).
She plays on the team every year for the rest of her time at Hogwarts, making it again in her seventh year with Harry Potter as Captain of Quidditch:
After two hours, many complaints, and several tantrums, one involving a crashed Comet Two Sixty and several broken teeth, Harry had found himself three Chasers: Katie Bell, returned to the team after an excellent trial; a new find called Demelza Robins, who was particularly good at dodging Bludgers; and Ginny Weasley, who had outflown all the competition and scored seventeen goals to boot (HBP11).