The article discusses conceptualisation of populism, Lithuania’s party system and electoral dynamics and their relation to the sustainability of populist parties. Special attention is given to Party Order and Justice, a former populist and protest party, and its leadership, namely to the issues related to scope and competencies of a leader’s intra-partisan power, leadership selection rules and history, development of leaders’ political careers and their electoral activity. The L ithuanian party system now exhibits moderate fragmentation without centrifugal tendencies. Voter volatility is still relatively high, yet the share of new parties has dropped to zero. The protest and populist parties in Lithuania went into the margins of political establishment. Popularity of the Order and Justice party has long been connected to the formerly impeached president Rolandas Paksas. His long-term leadership in the face of plummeting electoral support and an emphasis on his political martyrdom resulted in poor electoral performances, ensuing internal squabbles and his departure. Party Order and Justice’s internal regulations, however, remained favourable to strong leadership.