By means which have never been fully explained, he acquired great wealth, and in the 1640s he purchased Galgorm Castle in Antrim from Sir Faithful Fortescue.
Unwilling to admit that he was simply a shrewd man of business, his enemies maintained that he was in league with the Devil, and had later contrived to cheat him out of a roomful of gold.
In fact, so far from being a Satanist, Colville was a sincere Anglican and a convinced supporter of episcopacy, in contrast to his wife, who was a Presbyterian.
Since the Church of Ireland, especially in Ulster, leaned increasingly towards Presbyterianism, this led to bitter clashes between Colville and many of his clerical colleagues, who unsuccessfully sought his excommunication.
He probably died in 1679 (some sources say 1670), and was succeeded in his estates by his only son, Sir Robert Colville, a member of the Irish House of Commons and the Privy Council of Ireland.