Birthplace:
- Ballinclay, Ireland

Birthdate:
- 7 June 1844

Nationality:
- Scottish

Height:
- 5 feet 9 inches

Family Background:
- The father was Charles Lionel Kirwan (d. 1862) of Dalgin Park, County Mayo, Ireland, a Justice of the Peace, Deputy Lieutenant, and High Sheriff of that County. He adopted the hyphenated name of Maitland-Kirwan upon marrying Elizabeth Maitland of Kircudbrightshire, Scotland. After Charles' death Elizabeth was listed as the owner of Gelston Castle, Castle Douglas, Kircudbrightshire.

At Sandhurst:
- No

Foreign Languages:
- French

Career before Halifax:
- Ensign, 15th Foot, 8 January 1864 (purchase)
- to 78th Highlanders by transfer, 22 March 1864
- Lieutenant, 2 October 1866 (non-purchase)

Postings while in NS Command:
- Halifax, 22 April 1871 to 25 November 1871

Career after Halifax:
- Captain, 15 March 1873
- retired, 21 July 1880

William Francis was the Maitland-Kirwans' second son. After the father's death in 1862, the mother, Elizabeth, was left in possession of Gelston Castle, Castle Douglas, Kircudbrightshire, which she may have owned before her marriage. As noted in the 'New Doomsday' survey of 1873 this estate consisted of 5 080 acres, and produced an annual income of £5 000.

Maitland-Kirwan was recommended for his first commission by the Earl of Lucan (of 'Charge of the Light Brigade' fame) who stated that the young man was the son "of a gentleman of high estate in Ireland and also in Scotland." This applicant's first preference for a regiment was the 79th Cameron Highlanders. When he was posted to the 15th Foot instead, he requested that he be transferred to the Camerons as soon as a vacancy opened up. When one opened in the 78th instead, he wrote that he was "quite willing to accept the 78th in lieu of the 79th."

Maitland-Kirwan did not join the 78th in Halifax until April 1871. When it first came here he was serving with the depot company in Aberdeen, and then he apparently had been taken ill. The Horse Guards wrote to Hastings Doyle in January 1871 that he "had been granted a leave of absence at the recommendation of a medical board until the 30th March next and that steps will be taken in due course to provide passage for him to Nova Scotia."

In 1889, nine years after he left the 78th, Maitland-Kirwan came into possession of the Gelston Castle estate. In Burke's Peerage of 1914 he is listed as a Justice of the Peace and Deputy Lieutenant of Kircudbright, and "Lord of the Barony of Gelston."