 He was the youngest of the five sons of Esmé Stewart, 3rd Duke of Lennox (1579-1624) by his wife Katherine Clifton, 2nd Baroness Clifton.His eldest brother was James Stewart, 1st Duke of Richmond, 4th Duke of Lennox.Lord Bernard was to be created Earl of Lichfield by King Charles I for his actions at the first and second Battles of Newbury and at the Battle of Naseby but he died of injuries received leading a sortie against besieging Parliamentary forces in the Battle of Rowton Heath in September 1645, before the requisite letters patent were drawn up.