On 20 Feb 1843 [his father] John Beresford 4th Marquess Waterford (age 28) and [his step-mother] Christiana Leslie Marchioness of Waterford (age 23) were married. He the son of [his grandfather] Henry de la Poer Beresford 2nd Marquess Waterford and [his grandmother] Susan Hussey Carpenter Marchioness Waterford.

On 21 May 1844 John Beresford 5th Marquess Waterford was born to John Beresford 4th Marquess Waterford (age 30).

In 1865 John Beresford 5th Marquess Waterford (age 20) was elected MP Waterford which seat he held until 1865 when he succeeded in the Maequessate.

On 06 Nov 1866 [his father] John Beresford 4th Marquess Waterford (age 52) died. His son John Beresford 5th Marquess Waterford (age 22) succeeded 5th Marquess Waterford.

In 1874 John Beresford 5th Marquess Waterford (age 29) was appointed Lord Lieutenant of Waterford in which office he remained for his life.

On 21 Jul 1874 John Beresford 5th Marquess Waterford (age 30) and Blanche Somerset Marchioness of Waterford (age 18) were married. She by marriage Marchioness Waterford. She the daughter of Henry Charles Fitzroy Somerset 8th Duke Beaufort (age 50) and Georgiana Charlotte Curzon Howe Duchess Beaufort (age 49). He the son of John Beresford 4th Marquess Waterford.

On 28 Apr 1875 [his son] Henry de la Poer Beresford 6th Marquess Waterford was born to John Beresford 5th Marquess Waterford (age 30) and [his wife] Blanche Somerset Marchioness of Waterford (age 19).

On 30 Apr 1877 [his daughter] Susan de la Poer Beresford was born to John Beresford 5th Marquess Waterford (age 32) and [his wife] Blanche Somerset Marchioness of Waterford (age 21).

In 1879 [his daughter] Clodagh Beresford was born to John Beresford 5th Marquess Waterford (age 34) and [his wife] Blanche Somerset Marchioness of Waterford (age 22).

The London Gazette 25485. At the Court at Windsor, the 27th day of June, 1885. Present, The Queen's Most Excellent Majesty in Council. This day the Most Honourable John Henry (age 41), Marquess of Waterford, K.P., was, by Her Majesty's command, sworn of Her Majesty's Most Honourable Privy Council, and took his place at the Board accordingly.

The London Gazette 25485. Master of thee Horse's Office, Royal Mews, Pimlico, June 27, 1885. Her Majesty has been graciously pleased to appoint the Right Honourable John Henry Delapoer (age 41), Marquis of Waterford, K.P., to be Master of Her Majesty's Buckhounds, in the room of the Right Honourable Richard Edmund St. Lawrance (age 56), Earl of Cork and Orrery, K.P., resigned.

The London Gazette 25561. Master of the Horse's Office, Royal Mews, Pimlico, February 17, 1886, Her Majesty has been graciously pleased to appoint the Right Honourable Charles Harbord (age 56) Baron Suffield, K.C.B., to be Master of Her Majesty's Buckhounds, in the room of the Rigth Honourable John Henry Delapoer (age 41), Marquis of Waterford, K.P., resigned.

On 09 Oct 1895 [his brother-in-law] Henry Adelbert Wellington Fitzroy 9th Duke Beaufort (age 48) and Louise Emily Harford 9th Duchess Beaufort (age 31) were married. He the son of [his father-in-law] Henry Charles Fitzroy Somerset 8th Duke Beaufort (age 71) and [his mother-in-law] Georgiana Charlotte Curzon Howe Duchess Beaufort (age 70).

On 23 Oct 1895 John Beresford 5th Marquess Waterford (age 51) committed suicide. His son [his son] Henry de la Poer Beresford 6th Marquess Waterford (age 20) succeeded 6th Marquess Waterford.

On 22 Feb 1897 [his former wife] Blanche Somerset Marchioness of Waterford (age 40) died. The Graphic (London, England), Saturday, February 27, 1897: Much regret will be felt at the death of Blanche, Marchioness of Waterford. She was the only daughter of the eighth and present Duke of Beaufort, and was born in 1856. In 1874 she married the fifth Marquis of Waterford, who died in sad circumstances in October, 1895. Lady Waterford had been suffering for some years from a severe illness from which there was no hope of recovery, and her husband’s death gave her a severe shock. Last year, at the coming of age of the present Marquis, she had regained some of her strength, but the improvement was not maintained, and she gradually grew worse until she died on Monday morning at Curraghmore, County Waterford. Lady Waterford leaves one son (the present Marquis) and two daughters, the Ladies [his daughter] Susan (age 19) and [his daughter] Clodagh (age 18) de la Poer Beresford.