Johanna is Dawn's mother and a former Grand Festival champion. She's best known for having been an accomplished Pokémon Coordinator in her prime, and Dawn's entire reason for pursuing contests was to follow in her footsteps. When Dawn set out on her journey, Johanna gave her one of her old ribbons as a keepsake.
She made her anime debut in "Following A Maiden's Voyage!" and has stayed involved in the competitive coordinator scene ever since—she runs a Coordinator class from her home and even maintains a private battlefield for training her students, so her skills have never really dulled despite motherhood. As a young girl, she competed against her childhood rival Lila, and she's also surprisingly handy; she sewed the vest that Buneary wears.
Johanna first met Ash and Brock in person in "Strategy Begins at Home!" She demonstrated just how sharp her battling remains by taking them on in a double battle alongside Dawn, using Glameow and Umbreon to win handily. In "Battling a Cute Drama!" she helped out by sewing new outfits for the group. She also hosted a tournament at the Twinleaf Festival in "Challenging a Towering Figure!" looking formal in a gown for the occasion.
She appeared throughout the Sinnoh Grand Festival arc, showing up in the audience to watch her daughter compete—first in brief cameos during the earlier rounds, then returning in person for the finals.
Content compiled by AnimeList.moe from publicly available sources.