In later life, embittered by his chronic state of poverty, lack of professional advancement and failing military career, he espoused the Jacobite cause, and died in exile in France.
Robert for a time shared in his brothers' prosperity, and acquired estates in County Monaghan, but he soon fell into difficulty and suffered years of financial embarrassment.
By his own account, the blame for his financial problems lay entirely with the English Crown, which failed to pay his wages or offer him further advancement: he claimed that for many years he paid his soldiers out of his own pocket, and that he was ultimately forced to sell his estates as a result.
Unlike Henry, he was not a barrister, but it is noteworthy that he was admitted to the King's Inns as an honorary member, an unusual but not unprecedented honour for a layman, and a tribute to his services to the Crown.
When his uncle, Sir Albert Cunningham (who had married his aunt, Margaret Leslie), raised the Iniskilling Dragoons later that year Echlin was appointed Lieutenant-Colonel.
The Jacobite court noted with disappointment that only a handful of Ormonde's followers were prepared to make this sacrifice, and that those like Echlin who did so were mostly ruined men with nothing to lose and nothing to offer.
During the abortive Jacobite Rising of 1715 he was sent to Scotland: after "running great hazards", he reached the Orkney Islands, seized a vessel and returned to the Continent.