The Festival was founded in 1921 as the Thanet Competitive Musical Festival. No documents survive from that year, but it is clear from later references that the Secretary from the start was Miss Olive Raven. She was a person of boundless energy, who continued as secretary for over forty years, and was the life and soul of the Festival.

The first Adjudicator was Geoffrey Shaw, a well-known composer of music for schools, and brother of the better known composer, Martin Shaw. He came as Adjudicator at least three times in the first ten years of the Festival.

In the second year the Adjudicator was Harvey Grace, a well-known organist of the time, and editor of The Musical Times. The Isle of Thanet Gazette that year was refreshingly outspoken in its criticism of various aspects of the festival: "the public taste has been modified, not for the better, in recent years", "lack of interest on the part of Margate residents", "two rather uninteresting pieces", "one of the few good examples of male voice singing, so rare in Thanet", and so on.

In 1923, for Geoffrey Shaw's second visit, there was massed singing of Parry's Jerusalem, then a comparatively recent song. The newspaper report shows that the majority of the classes were for choirs, especially Elementary Schools and Girls' Clubs. The only Instrumental classes were violin and piano, piano duet and piano trio; there seems to have been no piano solo class.

In 1924 the Adjudicator was Sir Richard Terry, organist of Westminster Cathedral, and arranger of sea shanties

In 1925 the Adjudicator was Thomas F. Dunhill, who presented a shield to the Festival. He seems to have had local connections, as he is quoted as having written his setting of Bunyan's Pilgrim Song while walking along the beach between Margate and Broadstairs. He also composed a song called Thanet for massed singing at the next year's Festival. The accounts for the year show the receipts from the sale of this song were �4 5s 0d, and that it had cost �4 4s 7d to print: the Festival made a profit of 5d (old pence)!

In that year photographs of three school choirs appeared in the London Daily Graphic. Thorton Road School in Ramsgate seems to be singing while squatting on the floor! The engagement is also announced in the paper of Mr Stanford Robinson, a BBC Conductor, who was to be one of the Adjudicators some 40 years later.

In 1927 Geoffrey Shaw came again: he commented on '... Progress since I last heard you all; you have sprung up in a most wonderful way.' That year there were no less than ten classes for school choirs.

In 1929 Elocution seems to have been included for the first time. The winner in the class for Male Voice Choirs was RAF Manston.

In 1929 Geoffrey Shaw came yet again. Folk Dancing appears for the first time, and there were seven Women's Fellowship choirs. In those days not only the results, but also the Adjudicator's comments were published in local papers (three of them!) One wonders what the ladies thought of any derogatory remarks being made public in this way.