20 Aug 1804 Hospital Mate on the Medical Staff. Was sent out to Gibraltar during the fever of 1804.
Nov 1804–Nov 1808 Served in Gibraltar and Sicily.
20 June 1805 Appointed Assistant Surgeon 10th (North Lincolnshire) Regiment of Foot.
9 Nov 1809 Reduced to half-pay 10th Foot
being from ill health incapable of service.
23 Aug 1810 Recalled from half-pay and appointed Assistant Surgeon 71st (Glasgow Highland Light Infantry) Regiment. Was present during the whole of the Campaign of 1812 with the 2nd Division under Lord Hill in the advance on Madrid and subsequently under the Duke of Wellington in the retreat from Salamanca as assistant surgeon 71st Foot. He was present at Almarez and the retreat from Burgos.
4 Mar 1812–18 Apr 1813 Served in the Peninsular War.
15 Oct 1812 Surgeon 28th (North Gloucestershire) Regiment of Foot.
2 Aug 1813 Married Mary Dehane at Walmer Kent.
10 Apr 1814–2 July 1814 Served in the South of France.
25 Dec 1814 Reduced to half-pay 28th Foot on the reduction of the 2nd/28th Foot.
4 Oct 1816 Birth of a son John Lightbody at Walmer Kent.
7 May 1818 Recalled from half-pay and appointed Surgeon 80th (Staffordshire Volunteers) Regiment of Foot.
22 Oct 1818 Birth of daughter Mary Margaret Ann Lightbody at Hull.
3 Dec 1820–31 Dec 1829 Served in Gibraltar, Malta and the Ionian Islands.
18 Apr 1821 Birth of a son Thomas Dehane Lightbody at Gibraltar.
Malta 21 Aug 1821 Arrived from Gibraltar.
Malta 1822 In charge of his regimental hospital.
Malta 1823 Observed that troops attacked by fever during the summer, were those who had been on duty at the upper part of the Grand Harbour near Marsa.
29 Dec 1823 Birth of a son Francis Lightbody at Malta.
Malta 1824 In charge of his regimental hospital.
24 Jan Francis Lightbody son of Surgeon John Lightbody and Mary, born on 29 December 1823 was privately baptised on 24 January 1824 and received into the church on 15 January 1827.
Malta 1825 In charge of his regimental hospital.
Malta 1826 In charge of his regimental hospital.
12 Dec 1826 Birth of a daughter Emily Calvert Lightbody at Malta.
Malta 1827 In charge of his regimental hospital.
15 Jan 1827 Thomas Dehane Lightbody son of Surgeon John Lightbody and Mary, born on 18 April 1821 who had been privately baptised by the Rev M A Mackeneth at Gibraltar was publicly received into the church by Archdeacon John Thomas Howe Le Mesurier on 15 January 1827.
15 Jan 1827 Baptism of Emily Calvert Lightbody daughter of Surgeon John Lightbody and Mary, born on 12 December 1826.
Malta 8 Sept 1828 The 80th Foot left Malta for service in the Ionian Islands.
13 Dec 1829 Birth of a daughter Jane Lightbody at Corfu.
14 Apr 1832 Birth of a daughter Eliza Sarah Lightbody at Belfast.
4 Dec 1835 Appointed Surgeon 2nd Dragoon Guards vice Surgeon Jeffreys Hateley who retired upon half-pay. Hateley died on 15 September 1836 having been in service since 1808. The vacancy in 80th Foot was filled by the promotion of Assistant Surgeon Joseph Ewing 80th Regiment. Staff Assistant Surgeon John Reid in his turn became Assistant Surgeon 80th Foot, vice Ewing. Gentleman Robert Keith Kynoch came off the waiting list and became commissioned Staff Assistant Surgeon vice Reid.
3 Mar 1837 Appointed Staff Surgeon from 2nd Dragoon Guards on the death of Surgeon to the Forces Robert Badenach on 14 February 1837. The vacancy in 2nd Dragoon Guards was filled by Surgeon James Dawn 8th Light Dragoons. Assistant Surgeon John Squair 93rd Foot, became surgeon 8th Light Dragoons vice Dawn. Consequently, Staff Assistant Surgeon William Cruickshank became assistant surgeon 93rd Foot vice John Squair.
2 Aug 1842 Retired upon half-pay and practiced at Walmer Kent. Surgeon Francis Sievwright MD was promoted staff surgeon of the first class from 9th Foot to fill the vacancy created by the retirement of Staff Surgeon John Lightbody.
21 Apr 1865 Staff Surgeon John Lightbody died in Edinburgh, aged 78 years. A family pedestal memorial was erected at Warriston Cemetery Edinburgh, Scotland.