Lawrence was born in Carnegie, Oklahoma. She began her career as a photographer's model at a very young age, and appeared in her first film at age 15, Billy Rose's Diamond Horseshoe (1945). In 1947 she was involved in an incident that seemed to foreshadow the stalking incidents that are so common today. While at the movies she was stabbed by an unknown assailant. The wound was so deep that she was treated at the Santa Monica Emergency Hospital. The assailant was never found.
She was featured in the 1947 swashbuckler, "Captain from Castile" with Tyrone Power. While finishing her studies at UCLA, she ttracted the attention of talent scouts, and Lawrence was soon co-starring in a handful of 20th Century Fox movies, including A Letter to Three Wives, The Street with No Name, Thieves' Highway and Here Comes the Nelsons. In 1947, at age 17, she married another actor, John Fontaine, but the couple divorced the next year.