The son of Sir John Mordaunt, he was born at Walton Hall in Warwickshire.
The name "Osbert" has been used by members of the Mordaunt family since the 12th century, in honour of a direct ancestor of that name.
[4] He batted twice in the match and made scores of 6 and 5, being dismissed by Stirling Voules and Edward Kenney respectively.
[5] He played below first class level for the counties of Warwickshire, Staffordshire, Cheshire and (in one match in 1867) for Shropshire.
[6] He was described in Scores and Biographies as a "capital hitter and a good field, generally at point or slip.