Companies are seeking methods to become more innovative. One strategy is to introduce disruption to promote innovation. An example of this is the uptake of Open Source Software (OSS) technologies, methods and mindsets by commercially driven actors. Contrary to the firm, open source is associated with hackers driven by a passion emerging out of a community or peer based innovation model. The fact that these hackers are highly engaged in collaboration outside the limits of the organisation, have meant that companies start to perceive them as potential resources enabling them to extend their innovative capacity. The passionate hacker is seen as an autonomous and positive disruptive force that can promote innovation for the company. This paper is based on an interview study with 30 software developers from ten companies that have chosen to introduce OSS as a vehicle for innovation. Theoretically, passion is understood as an urge to develop high quality software beyond the demarcations of the firm; it is a matter of craft or art, and the paper focuses on how this perception of the passionate hacker guides these professional developers at work. Thus, it is analysed how the discourse on the passionate hacker is transformed when it is adopted by developers working in a firm that expects organisational commitment. By studying the reshaping of these software developers’ practices, we show how OSS passion for disruptive innovation is transformed in a professional work environment, but also how disruption creates new demarcations when open source ‘culture of passion’ is introduced in firms.