A left-handed batsman and occasional right arm bowler, Kinneir made his debut for Warwickshire in 1898 and played for the team until 1914. ‘Possessing exceptional grace of style without the exaggeration of pull that so often marks a left handed batsman’.
Overall he was credited with scoring 15,721 runs in 312 appearances for Warwickshire. Sep played in one Test Match in 1911 opening the batting against Australia in Sydney with Jack Hobbs scoring 22 and 30. The tour had come as a reward for his most prolific season with the bat, when he scored 1,629 runs in 20 matches, including a career best 268 not out, at an average of 49.36. He was named one of Wisden’s five Cricketers of the Year in 1912 and was considered to be one of the finest batsmen that ever played for Warwickshire. His brother, Arthur, played for Corsham 1st XI for over 20 years and captained the club during some very successful seasons.
Sep died in on October 16th 1928, aged 55, whilst motor cycling on his way home from playing golf.