 Forrest akaberekerwa muLondon, mwanakomana wechipiri waLieutenant-Colonel William Forrest weBengal Army, nemudzimai wake, Georgiana Christina Carmichael-Smyth, mwanasikana waJames Carmichael Smyth uye hanzvadzi yaSir James Carmichael-Smyth, 1st Baronet. Akabatana neHondo se cornet muna 1836, uye akasimudzirwa kuva lieutenant muna 1839, captain muna 1841, mukuru muna 48, brevet lieutenant-colonel muna 1854, lieutenant-colonel muna 1859, colonel muna 1860, major-general muna 1868, lieutenant-general muna 1877 uye general yakazara musi wa 1 Chikunguru 1881. Akarwa muHondo yeCrimea uye akatora chikamu muKupomerwa kweHeavy Brigade paBalaclava. Akagadzwa CB muna 1875 Birthday Honours. 