His first championship was achieved by beating William Cook 1,000–522 on 14 April 1870 at
St James's Hall. On 30 May 1870, in the minor hall, St James's Hall, he beat Alfred Bowles of Brighton 1,000–752. On 28 November 1870 Roberts lost the championship by 95 points, losing to
Joseph Bennett. He regained the championship on 30 January 1871, beating the same player 1,000–637.
Willam Cook defeated Roberts by just 15 points, in a match on 25 May 1871 to take the championship. Roberts lost to Cook by a margin of 201 points on 4 March 1872. And lost again to the same player by 216 points on 24 February 1874. He won the championship for a fourth time on 24 May 1875, in a 1,000–837 victory over Cook at
The Criterion. . On 20 December 1875, at St James's Hall, he defeated Cook by 135 points to win the championship. The match was witnessed by the Prince of Wales. Another victory for Roberts was achieved on 28 May 1877, with a 1,000–779 win over Cook at the Gaiety Restaurant,
Strand, London. Roberts challenged Cook for the title and was declared champion in February 1885 by default, without a game being played because Cook failed to respond to the challenge within the required time of two months. But then Cook challenged Roberts for the title, and this was promptly accepted. Roberts had been suffering from an attack of Malaria which had stopped him being able to practice a week before the match, and he was hobbling around the table during play. But he beat Cook by a margin of 92 points, on 1 April 1885 at the Argyll Billiard Hall in London. He won the last of his championships in a match that took place between 1–4 June 1885 at the
Royal Aquarium. John Roberts beat Joseph Bennett 3,000–1,360. ==Formation of the billiards association==