Her father, Thomas Worthington, was Governor of Ohio, 1814–18, and also served in the United States Senate. On 15 May 1816, she married Edward King, son of Rufus King of New York, who died 6 February 1836; and in October, 1844, she married William Peter, British consul at Philadelphia, who died 6 February 1853.
During her residence at Philadelphia she founded, 2 December 1850, the School of Design for Women now Moore College of Art & Design. Today, Moore College of Art & Design annually enrolls more than 500 women in its undergraduate BFA program. She worshiped at St. Peter's Church, Philadelphia at Third and Pine during this time. Returning to Cincinnati she spent most of her remaining years as a patron of art, and in works of charity and philanthropy.
She became a Catholic convert at Rome in March, 1855, being instructed there by Mgr Mermillod. The foundations of the Sisters of the Good Shepherd, the Sisters of Mercy, the Little Sisters of the Poor in Cincinnati, and other institutions, owed much to her generosity. In 1862 she volunteered as a nurse, and went with the sisters who followed General Grant's army in the south-west after the battle of Pittsburg Landing.
- King, Memoirs of the Life of Mrs. Sarah Peter(Cincinnati, 1889);
- Catholic Telegraph (Cincinnati), files;
- Freeman's Journal (New York), files.