Born in Helsinki, Ehrnrooth entered cadet school in 1922 and served in the Uusimaa Dragoon Regiment (Uudenmaan Rakuunarykmentti).
brigade | Charge of the Light Brigade | Brigade | Uusimaa | Upright Citizens Brigade Theatre | Boys' Brigade | Alpine Brigade Taurinense | ''Uusimaa'' | Upright Citizens Brigade | Rifle Brigade (Prince Consort's Own) | Persian Cossack Brigade | Finnish gunboat Uusimaa | Special Service Brigade | Provisional IRA Belfast Brigade | Golani Brigade | Brown Brigade | Alpine Brigade Tridentina | Girls' Brigade | Alpine Brigade Orobica | Alpine Brigade Cadore | 7th Canadian Infantry Brigade | Youth Brigade | New Zealand Mounted Rifles Brigade | Belfast Brigade | 3 Commando Brigade | Yiftach Brigade | Upright Citizen's Brigade | Paratroopers Brigade | Iron Brigade | Abraham Lincoln Brigade |