A member of the Dominican Liberation Party, he was named President of the San Cristóbal Committee in 2001.

At the age of 8, along with his parents and brothers, he emigrated to the Province of San Cristóbal in head municipality, where he received primary and secondary education in the Loyola Polytechnic Institute, standing out for its discipline and integration.

He was elected as deputy to Congress National by the Province of San Cristóbal in the period 2002-2006, becoming a member of the Finance, Telecommunications, Budget and External Debt Commissions.

In 2006 he was elected as Senator of the Province of San Cristobal by the Dominican Liberation Party (PLD), for a period of four years.

In the congressional and municipal elections of 2010, Tommy Galán Grullón was presented again as candidate for Senator of the San Cristóbal Province by the PLD and its allies, resulting winner and reelected as Senator for San Cristóbal, for the period 2010-2016, with more than fifty per cent of the votes cast.