Despite the relevance and maturity of the Chief Information Officer (CIO) research field, no studies exist that exhaustively summarize the current body of knowledge, focusing on the development of the field over its entire timespan. The paper at hand addresses this research gap and presents an exhaustive literature review on the CIO research field using main path analysis. We identify the central papers in CIO research and eight main research streams by quantitatively and qualitatively analyzing 466 papers. We find that established research streams, e.g., 'Evolving role of the CIO' and 'CIO hierarchical position and relationships' as well as recently emerging research streams, e.g., 'CIO as business enabler' and 'CIOs and IT security,' draw growing attention. Based on our findings, we develop promising further avenues for research in the CIO field.