Soren was inclined toward ethnic solidarity from an early age and associated with several prominent activists. In 1939, at the age of 21, he became a member of Raghunath Murmu’s association "Ol Samiti" to promote the Ol Chiki script for Santali literature.[3] His interest in tribal issues further deepened during his work in the court of the Mayurbhanj State at Baripada. Influenced by Jaipal Singh Munda’s organization Adivasi Mahasabha and its demand for tribal autonomy, he also founded the Mayurbhanj Adivasi Mahasabha in 1946, with its headquarter in Rairangpur, and served as its president.[2][4]
After India’s independence, on 16 September 1947, Soren wrote to Maharaja Pratap Chandra Bhanjdeo of Mayurbhanj expressing his wish for the state to merge with a proposed Jharkhand. Recognising tribal political aspirations, the Maharaja appointed Soren and other tribal leaders to the state assembly and the cabinet. Soren became leader of opposition in the house.[5] The sentiment then shifted toward remaining an independent state. However, with the Vallabhbhai Patel-led integration of princely states into India, Mayurbhanj’s independence was considered unfeasible. On 16 September 1948, Soren demanded a plebiscite on the state’s future, and also led a rally in Baripada from 2 to 6 November 1948. But, in view of conflicting political aspirations among leaders in the state assembly and social mismanagement, the Maharaja signed the merger agreement with India on 9 November 1948. On 1 January 1949, Mayurbhanj officially merged with Odisha. Subsequently, dissatisfied Soren led Mahasabha declared a civil disobedience movement on 8–9 January 1949, after V. P. Menon rejected their demand, which turned violent. Soren and other leaders were arrested on 4 February 1949.[2]
His arrest led to the Gunduria incident (6 February – 18 April 1949) in the Rairangpur subdivision, which lasted for two months. On 19 April, Premier of Odisha Dr. Harekrushna Mahatab visited Rairangpur to assess the situation. Following this, criminal cases against Soren and others were withdrawn, and they were released from jail.[2] After his release, Soren went to Ranchi, aiming to continue the agitation from outside Odisha.[6]
Soren came to Odisha from Ranchi after political invitation, and contested the 1952 Odisha Legislative Assembly election from Bahalda on the base of his organisation as an Indian National Congress candidate and became the constituency’s first MLA.[6] Due to his role in tribal politics, he was appointed Minister for Tribal and Rural Welfare, Commerce, and Labour in Nabakrushna Choudhury’s cabinet from 20 February 1952 to 19 October 1956. After two year being elected to the assembly, he merged his organisation into Nikhil Utkal Adivasi Congress to counter the territorial claims of Jharkhand Party.[7][6]
He lost the 1957 election to independent candidate Surendramohan Hembram but regained the seat in 1961 as a Congress candidate. In 1966, when the Congress in Odisha split to form the Orissa Jana Congress, Soren joined the Odisha fraction and retained his seat in the 1967 election.
In later two elections, he lost to Jharkhand Party and independent candidate Sashibhusan Marandi, contesting as a Jharkhand Dal candidate. In 1977, he won back the seat as a Janata Party candidate and served until 1980.
