Educated at Putney College in Surrey, Smyth was commissioned in to the 2nd Queen's Royal Regiment in 1841.

[1] He went straight to India only returning with his Regiment to England as Adjutant of his Battalion in 1846.

[1] He went to South Africa in 1851 to protect the administration of the Orange River Sovereignty from attack by the Basotho and Khoikhoi people.

[1] In 1861 he was appointed Inspector-General of the Militia in Ireland and was involved in suppressing the early stages of the Fenian Rising.

[1] He was appointed General Officer Commanding British Troops in Mauritius in 1870.