Many commentators have noted that since the 2014 Indian general elections, India has witnessed a new style of election campaigning that marks a decisive break from the past. Driving this change are a series of actors such as political consultants, 'spindoctors', campaign strategists, and specialised party staffers who have become an integral part of election campaigns and the routine affairs of party politics. In this thesis, I label such actors as 'political professionals' and analyse the changes ushered by them as a process of 'professionalisation of politics'. Although the professionalisation of politics has been noted in different countries around the world, this phenomenon has not received any academic attention in the context of a developing country. Based on a 12-month period of fieldwork in New Delhi, this thesis provides an empirically grounded examination of the manifestations, causal explanations, and implications of the professionalisation of politics in India. This thesis is divided into two parts - the internal and the external aspects of professionalisation. In the first part of the thesis, I focus on the internal reconfigurations taking place within India's political parties. In particular, drawing upon Panebianco's (1988) theory of an 'electoral-professional party', I analyse the growing importance of party employees in India's political parties and the concomitant declining emphasis on party bureaucrats. Through a study of two national level parties - the Indian National Congress (INC) and the Bharatiya Janata Party (BJP) - I analyse the different historical trajectories taken by parties to professionalise themselves, and discuss the various challenges and opportunities that come in its wake. In the second part of the thesis, I analyse the emergence and growth of political consulting firms in India. In an era of professionalisation, tasks that were once performed within political parties have gradually become outsourced to external political consultants who are hired on a contractual basis. Through an extended case study of Prashant Kishor, one of India's most famous political consultants, and the firms mentored by him, I demonstrate that political consultants in India adamantly disavow being portrayed as political mercenaries; instead, they fashion themselves as ethical citizens who are interested in making Indian politics more transparent, accountable, and non-corrupt through their profession. This thesis demonstrates the insufficiency of understanding professionalisation of politics as simply an outcome of socio-political modernisation. I argue that professionalisation is more than just the introduction of new technological innovations and specialised division of labour in political parties. Implicated in the process are new social imaginaries and competing political cultures that seek to reshape the meaning and practice of democratic politics. In doing so, the thesis shows that scholars need to pay greater attention to the 'backstage' of democracy - the arena of informal negotiations, deliberations, and strategising that takes place between political elites and their advisors and strategists. Understanding the professionalisation of politics, thus, provides a broader analytical window to understand the process of democratic deepening in the world's largest democracy.