Sarah Carter was born in Toronto, Ontario, and raised in Winnipeg, Manitoba. At school, she was a dancer and also took part in various school plays including portraying Dorothy in The Wizard of Oz. She was only a teenager when she began her acting career in the theater in A Chorus Line, The Sound of Music, and The Wizard of Oz. She was also a member of the debate team, which allowed her to travel all over the world. After graduation, she went to Neuchatel Junior College in Neuchatel, Switzerland, then joined Ryerson Theater School in Toronto, where she was discovered while performing a monologue.