She trained at the Arts Students League, the Pennsylvania Academy of Fine Arts, and the Academie Montparnasse in Paris. Oakley created oil paintings, stained glass windows, illustrations, and murals. The “Unity” frieze, a mural commissioned for the Pennsylvania State Capitol building, best expresses her vision of a peaceful world. At that time it was the largest mural commission ever awarded to a woman.
Oakley was also one of three women to receive the Gold Medal Award for distinguished service from the Pennsylvania Academy of Fine Arts. She received many commissions, including painting the first delegates of the League of Nations and the United Nations. Oakley’s illustrated books focus on the themes of world peace and human rights. She was a pacifist and a feminist.