At present, the Leader of the House in the seventeenth Lok Sabha(Lower House) is Mr Narendra Modi.
As per the context of the Indian Constitution, by default, Prime minister is the Leader of the House in Lok Sabha.
As per Article 75, the Prime Minister Shall be appointed by the President where the person must be the leader of the party elected with a majority of votes in General Elections.
The first leader of the House in Lok Sabha was Pt. Jawahar Lal Nehru who assumed the office for the first time on 2nd April 1952.