Ewart was educated at Christ Church College, Oxford (B.A., 1821), was called to the bar in 1827, and sat in the House of Commons from 1828 to 1837 and from 1839 to 1868. His work in Parliament secured the abolition of hanging criminals in chains as a form of punishment (1834) and of administering capital punishment for cattle stealing and other minor offenses (1837). From 1840 he urged the complete abolition of the death penalty; and in 1864, on his motion, the House of Commons appointed a select committee to consider the subject. (Capital punishment for murder was not abolished in Great Britain until 1965.)