In important tournaments he was a runner-up in the 1931 Irish Open and a losing finalist in the 1931 and 1933 News of the World Match Play.

Mary had an illegitimate son, Abe Mitchell, Mark's half-brother, who was also a successful professional golfer.

[2] He won the 1921 Golf Illustrated Gold Vase and turned professional later the same year.

He was unattached for a short period and moved to Scotland, joining Crow Wood Golf Club, Glasgow in 1932.

Seymour died in his shop at the North Shore Golf Club in Skegness, England on 16 September 1952 at the age 55.