Mr Pritam Singh joined the Workers' Party in 2010, and became an elected MP a year later, after his team scored a landmark victory at Aljunied GRC.
Last April, he was elected unopposed as the party's secretary-general, taking over the helm from veteran Low Thia Khiang.
The 42-year-old oversees the Eunos division in Aljunied GRC, and has proven popular with residents there. In the 2015 General Election, his ward had the highest vote share in the GRC, of about 55 per cent.
He graduated from the National University of Singapore in 1999, and was awarded the Straits Steamship Prize, given to the top history and political science undergraduate of each cohort.
A 2003 Chevening Scholar, under the British government's global scholarship programme, Mr Singh also holds a master's in war studies from King's College London.
He also holds a law degree from Singapore Management University's Juris Doctor programme.
Mr Singh is married to Ms Lovleen Kaur Walia and the couple have two daughters.
According to his biography on the WP website, "Pritam seeks to persuade more Singaporeans to build and strengthen the roots of democracy that earlier opposition stalwarts have courageously fought to create".
Mr Singh is the vice-chairman of the Aljunied-Hougang Town Council.