87 © Te Author(s) 2019 C. O’Riordan et al., Outsider Leadership, https://doi.org/10.1007/978-3-319-97463-7_5 5 Serial Outsider Leadership: Coming in from the Cold? Tis case study looks at a ‘serial outsider leader,’ sometimes described as a professional CEO (Boeker and Karichalil 2002). We use the term ‘serial’ purely in the context of someone who, through their career choices, has demonstrated some comfort with transitioning between organisations and sectors in a leadership role, thus making them an outsider on a num- ber of occasions. Fiacra Nagle, the studied leader here, has been CEO, MD or Executive Director of a number of organisations over his career, however he has not as yet started his own business (as of the timing of the case study). Terefore, this chapter afords us the opportunity to consider the role of a professional manager as an outsider leader entering an estab- lished organisation with a specifc purpose in mind. We focus on two of Fiacra’s professional CEO roles below, that of the frst CEO after the founder stepped down (O’Brien’s) and that of new leader in an organisa- tion facing business challenges that required change (Compass Group Ireland). An interesting feature of both of these roles is that Fiacra, with a background in banking, was a sectoral outsider as well. Tis chapter is written by Chris O’Riordan; Felicity Kelliher; Patrick C. Flood; Malcolm Higgs