Although a medical doctor and especially a member of the privileged class, he dedicated most of his working life to the poor. He agitated against deep-seated racism of the 1920s and 1930s which the planter class perpetrated against Blacks in education, religion, at the work place and in housing.

O'Neal is also credited with being the first politician in Barbados to campaign for improved conditions for women in the workplace, and the fact that women held leadership positions in the Democratic League and the Working Men's Association.

Historian Sir Alexander Hoyos has shown that "Adams' purpose after 1934 was to revive the political movement among the masses which O'Neal had started".  It could be said that O'Neal laid the foundation of social reform on which Sir Grantley Adams built so impresively after 1938.

In translating his vision for this island, O'Neal can count among his main achievements the creation of a network of grass-root organizations - the Democratic League which was a quasi-political group; the setting up of a proto-union - the Working Men's Association in 1926, and the launching of a co-operative venture in Bridgetown. He invested in a newspaper, "The Herald", which sounded the message of reform, enfranchisement and social change.

His work is particularly significant because it was the first time in the island's history that a man of O'Neal's class, who had a university education and was an independent professional, put his reputation on the line by aligning himself with the down-trodden.

Born in 1879 to Joseph and Catherine O'Neal he attended Trents Primary, the Parry School and went on to Harrison College, placing second in the examination for the Barbados Scholarship in 1899. His father sent him to Edinburgh University in Scotland to study medicine and he gained distinctions in almost all the academic areas and a Blue Ribbon in surgery.

It was there that he became a friend of Keir Hardie of the Independent Labour Party and his interest in politics grew.

O'Neal took the decision to run for a local government office and won a seat on the Sunderland County Council. At that time he was practising in the North England City of Newcastle. However, he had an over-riding desire to return home and spread the socialist doctrine to fellow citizens.

He came back to Barbados in 1910 and found the conditions so depressing that he went to Trinidad and Dominica to live and work. 

But the desire to serve Barbados compelled him to come home after 14 years and light a match under the authorities, forcing them to pay attention to the social ills of that day.

O'Neal founded the Democratic League in October 1924 and it won its first significant victory two months later when C.A. "Chrissie" Brathwaite was elected as a representative for St. Michael in the House of Assembly.

The League's programme was based on the principles of socialism and it attracted membership among the coloured and black middle classes.

The importance of educating ordinary people about politics also occupied O'Neal's time and energies to such an extent that he sparked their interest and some entered the political arena. He was the first black activist in this century to agitate for free education and free dental care for children; improved housing; and abolition of the infamous Located Labourers' System and the Masters and Servants Act. In addition, he campaigned ù although unsuccessfully - for the introduction of Universal Adult Suffrage.

In 1932, O'Neal finally won a seat in the House of Assembly as a Member for Bridgetown, defeating the prominent merchant H.B.G. Austin by one vote.

In Parliament, he continued his fight to improve the plight of the workers, was instrumental in securing an increased grant for the Barbados Scholarship winners, and campaigned for abolishing the despicable and degrading practice of child labour.

As might be expected, O'Neal was feared and even hated by his adversaries. However, when this outstandingly courageous Barbadian died on November 19, 1936, he left almost the entire community, including his foes, to acknowledge that he had played an exceptional role in arousing the political consciousness of the masses in the period leading up to the Disturbances of 1937.

Principal of the Cave Hill Campus of the University of the West Indies, Sir Keith Hunte, summed up O'Neal's life in the observation that he advocated a political creed based on "the simple, plain, direct principles laid down by Christ which emphasised the honouring of social obligations among members of the human society, while recognising that everyone was equal".

As testimony to the high regard in which he continues to be held, O'Neal's portrait appears on the $10 note while the Charles Duncan O'Neal Bridge in Bridgetown bears his name.