Kavanagh was a 36-year-old civilian in the Bengal Civil Service, an assistant commissioner in Oudh during the Indian Mutiny, when the following deed took place on 9 November 1857 at the Siege of Lucknow, India for which he was awarded the Victoria Cross:Mr. Thomas Henry Kavanagh, Assistant Commissioner in Oude On 8 November 1857.

Mr. Kavanagh, then serving under the orders of Lieutenant-General Sir James Outram, in Lucknow, volunteered on the dangerous duty of proceeding through the City to the Camp of the Commander-in-Chief, for the purpose of guiding the relieving Force to the beleaguered Garrison in the Residency, a task which he performed with chivalrous gallantry and devotion.

[3] In addition to the Victoria Cross, Kavanagh was promoted to be an assistant commissioner in Oudh, and helped in the suppression of scattered mutineers.

His medal (and a first edition of his book, How I Won The Victoria Cross) was held for more than 50 years by HistoricalMilitaria.com in Toronto, Canada.

The VC was sold at auction at Noonans Mayfair on 14 September 2022 for a record hammer price of £750,000.