A large literature exists on the influence of individuals on the origins of what became known as Australian Football. Less is known about the diffusion of the code and its rise to pre-eminence in other colonies where the institutional landscape was contested, with various forms of football evolving and competing for players and resources. Throughout the British Empire, dozens of variations of football based on fluid and changing rules emerged during the 1850s and 1860s. Institutional change theory suggests that while challenges to the status quo in established sporting activities may be resisted by gatekeepers who are committed to its traditions and shared meanings, other actors may leverage political capital to create institutions or transform existing ones. A case study of the establishment of Australian Football in Adelaide in the 1870s reveals that institutional change was driven by a local network of young, amateur sportsmen that saw the potential benefits of organized competition based on agreed rules. The work of a prominent member of this network, the English journalist R.E.N. Twopeny, is considered as an exemplar of the capacity of individual actors to mobilize support for institutional change.