Daniel Simon Letanka was born at Saulspoort in the Rustenburg district of the Transvaal in 1874 and attended the Native College in Grahamstown in the Cape. Hoping to raise money to continue his education overseas, he organised a choir that toured the Transvaal. When this scheme failed to produce sufficient income, Letanka became a court interpreter, working between 1902 and 1909 in the Supreme Court in Pretoria and at courts in Blaauwberg and Warmbaths. About 1910 he ventured into journalism, establishing Motsoaelle (the Friend)””subsequently renamed Morumioa (the Messenger), a weekly paper printed in Johannesburg but primarily serving Setswana speakers in the northern Transvaal. In 1912, with the urging of Pixley Seme and the financial backing of the Queen-Regent of Swaziland, the Morumioa was merged into the new Abantu-Batho, on which Letanka then worked as an editor for the next 20 years. A founding member of the South African Native National Congress (renamed the ANC in 1925), he was a vice-president of the Transvaal Congress for many years, a member of the committee that drafted the 1919 constitution, and a secretary of the House of Chiefs. Respected as a man of great integrity and diligence, he helped to solicit from chiefs the donations that were used to finance Congress deputations and court cases. In 1917 he helped to organise the election of a new executive committee for the Congress when a dispute between Seme and John L. Dube threatened to leave the organisation without leadership. When the Congress led protests after the jailing of sanitary workers in the "bucket strike" of 1918, Letanka was among five African leaders arrested and charged with incitement.
The government case collapsed, however, when an African police witness confessed that he had given false evidence. In 1922 Letanka took a case to the Supreme Court on behalf of the Congress, testing the validity of a 1921 Transvaal ordinance raising the African poll tax. He won the case, and the ordinance was voided. Shortly after Seme's election as ANC president-general in 1930, Letanka was dismissed from the Congress executive, along with several others, for arousing the ire of his longtime but autocratic friend. He died in 1932, penniless (according to Skota), after years of supporting himself on his small income from Abantu-Batho.