Kristin Amanda Thomas is President of the Baby-Sitters Club. She is described as athletic, outgoing, and slightly bossy. In the first few books, she is described as someone who doesn't care too much about clothes and make-up, but doesn't hate the idea. Later in the series, she is always described as wearing jeans, a turtleneck shirt and a sweater or sweatshirt.
In Kristy's Great Idea, she came up with the idea of the club. Because of that, she was elected President. She also came up with the idea for the club notebook, after sitting for two St Bernard dogs, Pinky and Buffy.
In Kristy and the Walking Disaster, Kristy came up with the idea for a softball team for kids who were too young or too poor of players for Little League. They named the team Kristy's Krushers.
Kristy's family is described as "blended." She has two older brothers, Sam Thomas and Charlie Thomas and a younger brother David Michael Thomas. Her mother Elizabeth Thomas married Watson Brewer in Kristy's Big Day. After the wedding, Kristy and her family moved across town to Watson's mansion, which he shares on the weekend with his children Karen Brewer and Andrew Brewer. In book #24, Kristy and the Mother's Day Surprise, Elizabeth and Watson adopt a two year old from Vietnam Emily Michelle Brewer.
Watson has a cat named Boo Boo. There are also two goldfish who live at Watson's who belong to Karen and Andrew. Their names are Crystal Light the Second and Goldfishie. Karen and Andrew also have two pets who travel back and forth with them: Emily Junior and Bob the Hermit Crab.
Kristy went to the Halloween Hop with Alan Gray in Claudia and the Phantom Phone Calls. This relationship soon fizzled out, and in Kristy and the Walking Disaster, she meets Bart Taylor, who is the coach of Bart's Bashers, the rival of Kristy's Krushers. They date casually for a while, and then in Kristy+Bart=?, Bart wants to get a bit more serious than Kristy would like and they break up for good. In Baby-sitters' European Vacation, Kristy meets Michel DuMoulin, a French Canadian. They triumph over Michel's love for the Blue Jays and fondness for playing the harmonica in public places to earn Kristy her first Vacation Boyfriend, a common BSC phenomenon.
Books Narrated by Kristy
#1 Kristy's Great Idea
#6 Kristy's Big Day
#11 Kristy and the Snobs
#20 Kristy and the Walking Disaster
#24 Kristy and the Mother's Day Surprise
#32 Kristy and the Secret of Susan
#38 Kristy's Mystery Admirer
#45 Kristy and the Baby Parade
#53 Kristy for President
#62 Kristy and the Worst Kid Ever
#74 Kristy and the Copycat
#81 Kristy and Mr. Mom
#89 Kristy and the Dirty Diapers
#95 Kristy + Bart = ?
#112 Kristy and the Sister War
#118 Kristy Thomas, Dog Trainer
#122 Kristy in Charge
#129 Kristy at Bat