Lucas was born in Ireland as the eldest son of Theobald Dillon and his wife Sarah Bourke.

Thomas Dillon, the 5th Viscount died without surviving children a year later.

On 28 February 1675 he granted a yearly pension of £600 (about £110,000 in 2023[12]) to Elizabeth, the widow of the 5th Viscount.

[16] On 22 September 1675 Lord Dillon obtained from King Charles II the waver of the quit rents to the amount of £455 13s.

[19] His widow married secondly Sir William Talbot, 3rd Baronet and died after 14 July 1710.