[2] After school he joined the University of Ceylon, Peradeniya as an external student and graduated with a bachelor's degree.

[2] Senathirajah got involved in the Sri Lankan Tamil nationalism movement at a young age and took part in the 1961 satyagraha.

[3] In 2013, Senathirajah caused a stir when he requested TNA party members to nominate him as the chief ministerial candidate ahead of the Northern Provincial Council Elections.

[17][18] India strongly opposed the planned attempt to nominate Mavai Senathirajah as the chief ministerial candidate by TNA party for the 2013 Northern Provincial Council Elections considering his past history of having formed deep rooted friendship with members of the LTTE.

[19] Senathirajah's decision to step into the candidacy baffled Sampanthan as he initially planned to nominate C. V. Vigneswaran for the chief minister position for the 2013 Northern Provincial Council Elections.

[17][22] Senathirajah marched on his way to dethrone the longstanding leader R. Sampanthan, as the latter held onto the party leadership position of ITAK fron 2004 to 2014 for nearly a decade.

During those years when Sampanthan held onto the leadership position of ITAK, Senathirajah continued to serve in as the general secretary of the party.