Carol Spencer spent more than 35 years working at Mattel, Inc., designing clothing and accessories for the company's very popular Barbie Doll. Her designs produced the Sew Free Fashion line in which young girls made their clothes for Barbie and the My First Barbie Doll with a line of clothing suitable for the small hands of the three- and four-years olds who became the doll's youngest fans. Spencer also worked on Barbie's Baby Sister Kelly in the early 1990s, and her 1992 Totally Hair Barbie became the best-selling Barbie of all time. In addition, in 1989 Spencer developed the first Barbies for the newly established Collector Division for adult fans of the doll. Spencer worked on other toy lines for Mattel, but she most definitely left her distinctive on Barbie.