Seymour scored more than 1,000 runs in a season 16 times, including in all four Championship winning years, and made 2,088 in 1913, 1,932 of them for Kent, at the time the second highest aggregate scored during a season for Kent to Wally Hardinge who scored 2,018 runs during the same season. He is fifth on the list of all time run scorers for Kent with 26,818 and scored 53 centuries for the County which remains the sixth highest number scored for Kent in first-class cricket.