The ever-increasing prevalence of chronic conditions over the last half century has gradually altered the demographic of patients admitted to acute care settings; environments traditionally associated with episodic care rather than chronic and complex healthcare. In consequence, the lifeworld of the hospital medical doctor often entails healthcare for a complex, multi-morbid, patient cohort. This paper examines the experience of providing complex healthcare in the pressurised and fast-paced acute care setting. Four medical doctors from two metropolitan health services were interviewed and (...) their data were analysed using a combinatorial framework of phenomenology and complexity theory. The horizon of complex care revealed itself as dynamic, expansive, immersive, and relational, entailing a specialised kind of practice that is now common in acute care settings. Yet this practice has made inroads largely without heralding the unique nature and potential of its ground. Herein lies opportunity for complex care clinicians to expand notions of health and illness, and to shape research, practice, and system design, for a future in which care for health complexity is optimised, irrespective of care settings. (shrink)