[1][2] Ross was born at Balnagown Castle, the son of Sir Charles William Frederick Augustus Lockhart-Ross, 8th Baronet and his second wife, Rebecca Sophia Barnes of Tufnell Park.

When he came of age he instituted a lawsuit against his mother for having, during his minority, spent more of the revenues of his estates than she was entitled to by law or by the terms of the will.

Ross was said to have been Britain's largest landowner, possessing Scottish lands extending to an estimated 366,000 acres (1,480 km2), with 3,000 tenants.

At one point, in an attempt to evade United Kingdom taxation on the income from his arms manufacturing, Ross declared his Easter Ross, Scotland estate of Balnagown to be a territory of the United States of America, which led to his being branded an outlaw for a time by the British Government.

Ross married three times: first to Winifred Berens (marriage dissolved in 1897); then in 1901 to Louisville debutante Patricia Burnley Ellison,[5] who divorced him in 1930;[6][7] and in 1938 to his American secretary Dorothy Mercado (née Harvey).