Biography
Kate Randall is Hanna Marin's soon to be stepsister. She seems to be someone who is poised and well-brought-up. It is also mentioned that she is good at sailing.
Season 1
She is introduced in "Can You Hear Me Now?" when Tom takes Hanna out to dinner. Hanna, thinking that she is to have a private evening with her father is shocked to see Tom greet Kate and Isabel in the restaurant. She is further shocked when she learns in that moment that Isabel is engaged to her father, making Kate poised to be his step-daughter.
During dinner, the conversation focuses on Kate and her latest achievements, as well as the fact that she is accomplished at sailing, while Hanna doesn't know how. None of them seem to find Hanna's jokes funny, while the subject of Kate seems ever fascinating. Adding insult to injury, Tom insensitively brings up Hanna's totaling Sean's car at this point in the conversation. And, despite Kate's seemingly wholesome demeanor, she behaves snarly towards Hanna: she shares a smirk with her mother as this is mentioned. But she does play nice by suggesting that Hanna's payback job might be interesting. Not to lose a beat, Hanna quickly mentions her fascination with "false veneers!" (Now that she needs to pay back Sean, she is to start working in his mom's dental office.)
Season 2
She is not seen again until "Touched by an 'A'-ngel" and is played by a different actress. She looks much different. She has longer, straighter, lighter blonde hair. Her eyes are now a medium brown as opposed to blue, a longer shaped face and is now much more fashionable.