Whilst the academic literature on leadership has identified authenticity as an important leadership attribute few studies have examined how authentic leadership is evaluated in naturally occurring discourse. This article explores how authentic leadership was characterised and evaluated in the discourse of the British press during the 2015 Labour Party leadership election - won, against the odds, by veteran left-winger Jeremy Corbyn. Using membership categorisation analysis, we show that the media discourse about authentic leadership was both ambiguous and ambivalent. In their representation of authentic leadership, we found that a discourse of ‘ethical’ leadership was played out in tension with a discourse of ‘effective’ leadership. We propose that this complex and contradictory discursive landscape is also relevant in business contexts where ‘ethical’ leaders are subjected to praise for their virtues but also criticism for their ineffectiveness. Future research could usefully study how ‘ethical’ leaders in different settings can be subject to competing evaluations when their ethical values are discursively contrasted to expectations concerning what it takes to be an ‘effective’ leader.