Before 07 Jan 1643 [his father] Harbottle Grimston 2nd Baronet (age 39) and [his mother] Mary Croke (age 33) were married.

On 14 Feb 1670 Samuel Grimston 3rd Baronet (age 27) and Elizabeth Finch (age 20) were married. She the daughter of Heneage Finch 1st Earl Nottingham (age 48) and Elizabeth Harvey Baroness Finch (age 43).

On 17 Apr 1673 Samuel Grimston 3rd Baronet (age 30) and Anne Tufton Lady Grimston (age 19) were married. They had a son and a daughter both of whom died young. She the daughter of John Tufton 2nd Earl of Thanet and Margaret Sackville Countess Isle Thanet (age 58).

On 16 Jun 1674 [his brother-in-law] Daniel Finch 2nd Earl Nottingham 7th Earl Winchilsea (age 26) and Essex Rich 2nd Countess Nottingham (age 22) were married. She the daughter of Robert Rich 3rd Earl Warwick and Anne Cheeke Countess Warwick. He the son of [his father-in-law] Heneage Finch 1st Earl Nottingham (age 52) and [his mother-in-law] Elizabeth Harvey Baroness Finch (age 47).

On 14 Aug 1684 [his brother-in-law] Thomas Tufton 6th Earl of Thanet (age 39) and Catherine Cavendish Countess Isle Thanet (age 19) were married. She by marriage Countess of Thanet. The difference in their ages was 20 years. She the daughter of Henry Cavendish 2nd Duke Newcastle upon Tyne (age 54) and Frances Pierrepont Duchess Newcastle upon Tyne (age 53). He the son of John Tufton 2nd Earl of Thanet and [his mother-in-law] Margaret Sackville Countess Isle Thanet.

On 24 Nov 1687 [his son-in-law] William Savile 2nd Marquess Halifax (age 22) and [his daughter] Elizabeth Grimston were married. He the son of George Savile 1st Marquess Halifax (age 54) and Dorothy Spencer Lady Savile.