McDowall was an assistant at the Links Golf Club, Newmarket before World War I.

[4] The following year he led by 7 strokes after 3 rounds but was caught on the final afternoon and lost a playoff.

[5][6] McDowall also won the inaugural Dunlop-Scottish Tournament played on the King's course at Gleneagles in October 1933.

[11][12] In 1935 he won the event, finishing 6 strokes clear of the field and 9 ahead of Seymour.

[13] McDowall was a regular competitor in the Open Championship, qualifying for 10 successive years from 1926 to 1935.