He was educated at Queens College Galway, where he was auditor of the college's Literary and Debating Society for two years, from 1860 to 1862, and at the King's Inns, where he was auditor of the Law Students' Debating Society of Ireland for the 1862–1863 session.
[citation needed] Monroe was called to the Irish Bar in 1863; he took silk in 1877 and became a Bencher of the King's Inns in 1884.
He had a good reputation in the legal field and was regarded as an expert on the Irish Land situation.
[4] A younger son, Horace, became a clergyman attached to St. Patrick's Cathedral, Dublin , and wrote a short history of his mother's family.
[5] The Moule marriage created a family tie with one of Ireland's foremost judges, Hugh Holmes, who married Elizabeth's sister Olivia.