He was a grandson of Sir Henry Johnson, 1st Baronet and great-grandson of Frederick Philipse III of New York.

[3] He was educated at the East India Company Military Seminary in Addiscombe.

[4] In 1877, while holding the rank of Colonel, he was made a Companion of the Order of the Bath.

Johnson was made Knight Grand Cross of the Order of the Bath (GCB) in the 1900 Birthday Honours.

[6] Johnson married on 4 January 1860 Jemima Anne Frances Martin (d 18 July 1920), daughter of Rev George Martin by Lady Charlotte Sophia Eliot, second daughter of the 2nd Earl of Saint Germans.