Twitch.tv (‘Twitch’) is a livestreaming platform known for the live broadcasting (‘streaming’) of videogame-related content. It is also the most popular livestreaming platform in most countries. Drawing upon over one thousand hours of ethnographic observation across twenty-one Twitch channels, and six months of part-time streaming, this thesis investigates how streaming persona is constructed and performed on Twitch. Streaming persona, the thesis posits, is to be differentiated from more straightforward readings of streamer identity as performance. This thesis instead shows that streaming persona is constructed and performed collectively by both human and nonhuman actors in a Twitch stream. It does this by intervening in five core areas of interdisciplinary concern. The first of these explores new ways of understanding perceptions of authenticity that are constructed and denied as a result of streamer decisions, including an analysis of ways that gendered streamer performances affect perceptions of authenticity. Secondly, this thesis presents a new perspective on the conflicting and negotiated agencies of different stream actors during a stream, including games and the Twitch platform as nonhuman actors. The third core area of interest extends existing scholarship on moderation and governance by investigating boundary-work as a playful activity performed by multiple stream actors, including focused examinations of boundary-work associated with game-centric practices, such as spoiling content, and toxic behaviours. Fourthly, this thesis presents a highly novel exploration of how time on Twitch is arranged and experienced differently by different stream actors and the associated temporal politics of the platform. And fifthly, it intervenes in existing research on both games and Twitch by examining (digital) games as stream actors that perform alongside the streamer, spectators, and platform, thereby presenting new ways to understand games, game play, and why streaming and spectating game play are compelling activities. The concept of streaming persona allows for an exploration of how social identities are constructed and performed through and with the Twitch platform and its users. As such, it provides novel insights into the sociality, culture, politics, and economics of Twitch.