Ewing was a trustee of Washington College from 1834 to 1887 and of Washington Female Seminary from 1846 to 1887.
He was a staunch supporter of the Union cause during the Civil War, and in 1862, at the age of 66, served as Captain of Company F of the 6th Pennsylvania Regiment of Militia, which was briefly called up and deployed to Chambersburg, PA, during Lee's Maryland invasion that September.