During his term of presidency (2004–2014), Indonesian President Susilo Bambang Yudhoyono (SBY) was heavily criticised for excessive use of English when making formal speeches in Indonesian, a linguistic phenomenon of mixing languages known as code-switching. Such criticisms reflect an ambivalence towards English that is influenced by nationalistic sentiment. By analysing a range of presidential speeches, we reveal that SBY’s code-switching was highly variable but not random, and depended largely on particular audiences, topics and domains. Despite certain instances where SBY avoided English code-switching, which suggests nationalistic self-positioning, findings show SBY frequently engaged in code-switching as part of his communicative repertoire. We argue that SBY used code-switching as part of his pragmatic competence to strategically enhance his credibility and authority. This demonstrates how English code-switching can be used strategically to enhance a leader’s political discourse in an Indonesian context.