Mighty Morphin EraEdit
She became a cat monster, but the form was eliminated by Ninjor and Ninja Megafalconzord. She can transform back and forth between her cat and human form.
While she was in her human form, she stole Kimberly's power coin, and snuck into the Falconzord and stole it after knocking Tommy out.
But Katherine would soon break free from the spell due to her pure heart. When she broke free, she was near Angel Grove's Gym & Juice Bar with Kimberly inside training for the Pan Global Games. When she got in she saw Kimberly, still weary from the last couple of battles, struggle to stay focused on the balance beam, she ended up losing her balance and fell on the floor. Katherine feeling guilty for being partially responsible, because she was involved in Rita's plan to tire Kimberly, took her to the hospital. When Tommy and Billy who went to visit Kimberly was called to help out Rocky, Adam, and Aisha, Katherine visit Kimberly and confessed about the things she did while she was influenced by one of Rita's spells but she knows about Kimberly and her friends being Power Rangers especially when Tommy told her about his experience of being influence by Rita. Rita and Zedd sent down Garbage Man to capture Katherine for breaking their dream of using her to destroy her new friends. But when Garbage Man failed Zedd and Rita gave the Rangers the ultimatum: Either they give up Katherine or their ally Ninjor will be sent to the bottom of the Sea of Sorrow.
The Rangers go through with the deal and had met with Rita, Rito, Goldar, and the Tengas but was tricked to find out that the container which contained Ninjor was empty as for the Rangers' plan B, they activated a shield protecting Katherine from evil. however the Tengas was able to destroy the shield allowing Rito to kidnap Katherine. while Katherine was in a dungeon as Rita and Zedd waited for the Sea of Sorrow's high tide, Rito who had a pain in his neck, was standing guard and allowed Katherine to massage his neck only to fall asleep after. As Katherine got the key from him and got out she noticed a box in which Rito told her what was inside it which was Kimberly's pink power coin, once she obtained it, she was teleported to the Command Center and was able to give the coin back to Kimberly. However, After successfully completing the Pan Global Trials and has the chance of competing in the Pan Global Games, Kimberly, with the support of her friends for going to the Pan Globals, decided to quit the team and passed her coin to Kat as she became the new Pink Ranger.
She becomes friends with Aisha and begins to love animals. Zedd and Rita captured her in a chamber and try to make Kat evil again, Tommy eventually came to the rescue after finding the Zeo Crystal in the Caves of Deception and frees Kat.
Master Vile used the Orb of Doom to transform all the Rangers back into children and Kat had to find her Zeo Crystal in the Australian Outback and found the Pink Zeo Crystal.
Then, the Zeo Crystals transformed the Rangers back into their normal selves except for Aisha who decided to stay in Africa and helped the African people to take care of animals and sends a girl named Tanya to take her place and also takes the Yellow Zeo Crystal.
After the Zeo Crystal was finally restored, she was given new powers and became Zeo Ranger 1: Pink. She and Tanya became close friends during the Zeo and Turbo era. She then meets Jason, the original Red Ranger and Tommy's old teammate and Jason became the Gold Ranger.
After Tommy becomes depressed about Kimberly breaking up with him, Kat decided to cheer Tommy up by taking him to snowboarding. After Tommy ended up losing Heather, she and Tommy begin to dance and Kat begins to have feelings for Tommy.
In "Good as Gold", she holds Tommy's hand as they are now a couple after Tommy bids Jason farewell as Jason has now lost his Gold Ranger powers after Tommy tells her that there's more to saving the world, showing that he loves her and she loves him.
In "A Season to Remember", she is currently married to Tommy and are grandparents and they have two grandchildren who is a Power Ranger.
After Billy left to live on Aquatar and Jason lost his Gold Ranger powers, the Zeo team was quickly dismantled.
The mysterious wizard Lerigot was hunted by a ruthless space pirate called Divatox and Zordon gives her, Tommy, Adam and Tanya new Turbo powers as she became the Pink Turbo Ranger.
After Rocky, the second Red Ranger and the Blue Zeo Ranger and Tommy and Adam's teammate made a wrong move and threw out his back and is unable to rejoin the Rangers, Justin was selected to take Rocky's place as the new Blue Turbo Ranger.
She became an older sister figure to Justin as Tommy becomes an older brother figure to Justin. She and the other Rangers battled a monster named Numbor and she became weightless, but the other Rangers reverted her back to normal.
She would fight a few more battles with Divatox and TJ and Cassie would help Kat fend off the Pranhatrons and rescue Tommy.
In the end, she chose Cassie to take her place as the new Pink Turbo Ranger and left for London to begin her career as a ballerina.
Is unknown if she is still together with Tommy or not, but most of fans think she and Tommy got married because the episode "A season to remember" suggested that would be his future.