Dromgoole was elected a Jacksonian and Democrat to the United States House of Representatives in 1834, serving from 1835 to 1841, declining reelection in 1840. He was later elected back in 1842, serving again from 1843 until his death on April 27, 1847, at his estate in Brunswick County, Virginia.
Dromgoole's political career began when he was elected to the U.S. House of Representatives in 1834 as a Jacksonian and Democrat, serving from 1835 to 1841 before deciding not to run for re-election in 1840. He later regained his seat in 1842, serving another term from 1843 until his death on April 27, 1847, at his estate in Brunswick County, Virginia.