 Singh was a General Secretary of College Students Union and in 1974, had participated in the movements led by Jayaprakash Narayan.Singh is married to Renu Devi and they have a daughter together.Lalan Singh represented the Munger constituency of Bihar and was President of Bihar JDU when he rebelled against CM Nitish Kumar in 2010 and later continued to be an unattached member of JD(U).