He attended Dickinson College and studied law with Charles Smith of Lancaster, Pennsylvania.

Ridgely was instrumental in the organization of the Farmer's Bank and served as its president in Dover for 40 years.

In 1827, he was elected to the United States Senate to fill the vacancy caused by the death of Nicholas Van Dyke and served out his term from January 12, 1827, until March 3, 1829.

He was not reelected to the next Congress because, in the great political realignment then underway, Ridgely had become a supporter of President Andrew Jackson, in opposition to the majority in the Delaware General Assembly.

Ridgely died at Dover on August 6, 1847, his 68th birthday, and is buried there in the Christ Episcopal Church Cemetery.