Richard Msimang was the son of Joel Msimang, founder of the Independent Methodist Church of South Africa, he was among the first pupils of the Ohlange Institute, founded by John Dube in Natal and later attended the Healdtown Institution in the Eastern Cape. Subsequently Msimang spent a decade in Britain where he trained and qualified as an attorney at Queens College, Taunton, Somerset.
In November 1910 he returned to South Africa and opened a legal practice in Johannesburg. At about that time he befriended political aware and overseas-educated black lawyers such as Pixley Seme and Alfred Mangena, who both influenced the way in which he cut his political teeth.
In 1912 Msimang was a founder member of the South African Native National Congress (SANNC, after 1923 ANC). As an expert on law he chaired the committee that compiled the 1919 constitution of the SANNC. After parliament had passed the Natives Land Act of 1913 he participated in the SANNC protest against it. He and the well-known Sol T. Plaatjie traversed the rural areas to investigate the effect of the said act on black people. Msimang compiled a list of evictions, which included the names of individuals and details concerning their livestock. In 1913 his findings were published in a pamphlet, Natives Land Act 1913 - Specific cases of evictions and hardship, etc., in which he condemned the outright. He also supports the opposition to the issuing of passes to women.
During the July 1913 SANNC conference held in Johannesburg to discuss the SANNC's rejection of the Natives Land Act, at an emergency committee was chosen to campaign for funds to send a deputation to Britain to protest against the Act. Msimang was a member of the committee, but not of the 1914 deputation to Britain. Directly after outbreak of the First World War he was, however, a member of the SANNC deputation that travelled to Pretoria to assure the government of black people's support for the war effort. As a legal advisor to the SANNC Msimang handled numerous cases involving the organization from 1917 onward.
During the strike by a sanitary workers employed by the Johannesburg municipality in 1918 he acted as a legal advisor to the strikers. They were nevertheless found guilty and sentenced to two months' hard labour. This led to a series of protest meetings by the Transvaal division of the SANNC, the Transvaal Native Congress (TNC). Riots broke out in the streets of Johannesburg. In an attempt to defuse the situation the government appointed a one-man commission in the person of J.B. Moffat to investigate the strike and the ensuing events. Msimang gave evidence before the commission on behalf of the TNC.
In April 1918 the government appointed a one-man commission in the person of George Boyes to investigate the alleged maltreatment of blacks during the SANNC's anti-pass campaign. Msimang appeared before the commission on behalf of the SANNC and made a very good impression on the commissioner. Msimang was the Assistant General Treasure of the 1921 TNC congress in Pietersburg that discussed the pass laws with the government commission investigating them at that time. He was elected to the five member special committee that had to study the government commission's report upon its publication and make recommendations. Msimang favoured closer contact between blacks and whites in South Africa. This is confirmed by his inclusion in the Joint Council's movement and his participation in the National European Bantu Conference of 1929, which aimed at bringing together blacks and whites to discuss their mutual problems.
His high standing in the black community and his interest in and involvement with sport are confirmed by election in 1928 as Vice-Chairman of the Provisional Committee of the South African Non-White Athletics Union, which was established in Bloemfontein in September 1928.
He also took an active interest in black soccer and was founder member of the Johannesburg Bantu Football Association in 1929.