Sandeep Lamichhane was born on 2 August 2000 in Aruchaur, Syangja, Nepal. During his childhood, Sachin Tendulkar and Shane Warne were his cricketing idols. Then he moved to Chitwan district. There he started training at Chitwan Cricket Academy which is run by former captain Raju Khadka. During a visit of current captain Paras Khadka and former coach of Nepal Pubudu Dasanayake, Sandeep was told to bowl in the nets. They picked him straight to the national camp for under-19.