The Championship started on Tuesday with 43 competitors, when the first and second rounds were completed in stormy conditions. In the semi-finals, Dorothy Campbell beat J. Rusack from Hilltarvit by one hole and faced the holder Miss Molly Graham from Nairn in the final. The game was all square after 18 holes and Campbell snatched victory on the nineteenth green watched by over 4,000 spectators.

Dorothy Campbell retained her Scottish title at Cruden Bay in 1906, beating the formidable Miss Alex Glover in the final. Again the following year Dorothy reached the final, this time at Troon but was defeated on the 21st hole by another North Berwick golfer Frances Teacher (Mrs. Mather). Dorothy won again in 1908, beating Miss M Cairns 7 and 6 at Gullane and was runner-up in 1909.

For the first time the British Ladies Championship of 1908 was held at St. Andrews. Dorothy entered from Musselburgh and faced Maud Titterton, also from Musselburgh in the final, when the entire town came out to watch, including Old Tom Morris. The final didn't start until three o'clock because the semi-final between Maud Titterton and the sensation of the event, seventeen year-old Cecil Leitch went twenty-two holes and by that time the Old course was covered in fog.

Estimates for the crowd around the first hole was 9,000 people and by the 11th, a terrible storm blew in hitting the two contestants with hail, rain and wind. Many of the greens were completely covered in water. Titterton's ball bounded through the Swilcan burn on the final hole allowing her to square the match. At the first extra hole, Titterton beat Campbell with a par-4 to her bogey-5. On the 27th May, two days after the final Old Tom Morris died. It is interesting to note that the Ladies were not given the freedom of the Royal and Ancient Clubhouse during the championship.

In 1906 at Cromer she played for Britain in a match against a United States group. There were seven players to a side, and Dorothy was No. 7 for the British team, which won by six matches to one. The American team was composed of the Misses Harriot and Margaret Curtis, Miss Frances Griscom, the two Phelps sisters, Miss Georgianna Bishop and a Mrs. Martin.

At Royal Birkdale in 1909, Campbell again entered the British Championship from Musselburgh. This was the first major event to be held at Brikdale and Dorothy defeated Ireland's Miss Florence Hezlet 4 and 3 in the final. She then took up an invitation to play in the American Championship of that year at Merion Cricket Club. Dorothy faced Mrs. Nonna Barlow from Ireland in the final. Barlow a member of the host club went out in 45 to Campbell's 46 and was one up. Barlow however missed a short putt on the ninth which would have given her a two shot advantage. Campbell won the eleventh and the thirteenth to take the lead, then won the fifteenth and sixteenth to win the match 3 and 2, to become the first foreign-born U.S. Champion and the first woman to hold both the British and U.S. Amateur titles. It was a feat that neither Glenna Collett nor Joyce Wethered who later dominated the game, accomplished.

The only tournament Campbell failed to win that year was the Scottish Amateur Championship played at Machrihanish when she was defeated in the final by E. Kyle. In 1910, Campbell moved to Hamilton, Ontario and won the first of her three in a row Canadian Amateur titles.

The USGA Woman's Amateur Championship trophy was donated in 1896 by Robert Cox from Gorgie in Edinburgh. He was Member of Parliament for the Edinburgh South Division and learned to play golf at Musselburgh while attending Loretto School. The Robert Cox Trophy, encrusted with Scottish thistles, and panels bearing scenes of St Andrews, is the only USGA trophy to be presented by a foreigner.

At the 1910 US Amateur Championship at Homewood C.C. Flossmoor, Illinois, Campbell scored a match-play 78 when she defeated Mary Fownes in the second round. It was the lowest score by a woman over a course of more than 6,000 yards, and it was reported in the American Golfer that the critics watching the championship described it as the most wonderful golf ever displayed by a female golfer in this hemisphere. Campbell at the top of her game, sailed through the early matches never going further than the fifteenth green in any of her victories. In the final Dorothy Campbell successfully defended her title by beating Mrs G. M. Martin of Devonshire, England 2 and 1. In 1911, she picked up her second Ladies' British Open Amateur Championship at Royal Portrush Golf Club, this time defeating Violet, the youngest of the three Hezlet sisters from Ireland. Dorothy coming from 3 down after eight, to win 3 and 2.