Rajan Sushant was involved in student politics since the Emergency when he was jailed. In 1982, he was elected as the youngest member of the Himachal Pradesh Assembly and went on to retain the position for 5 non-consecutive terms and was declared a candidate by the Aam Aadmi Party from the Fatehpur Assembly seat this time. He started his career as a youth leader and joined the Bharatiya Janata Party (BJP). However, criticising his own party led him to his suspension in 2011. He left the BJP a few months before the 2014 Lok Sabha polls. Between 2009 and 2014, he was also elected as the Member of Parliament on a BJP ticket from Kangra.