Objective: To assess current demographics and duties of physicians as well as the structure of paediatric cardiac critical care in the United States. Design: REDCap surveys were sent by email from May till August 2019 to medical directors ("directors") of critical care units at the 120 United States centres submitting data to the Society of Thoracic Surgeons Congenital Heart Surgery Database and to associated faculty from centres that provided email lists. Faculty and directors were asked about personal attributes and clinical duties. Directors were additionally asked about unit structure. Measurements and main results: Responses were received from 66% (79/120) of directors and 62% (294/477) of contacted faculty. Seventy-six percent of directors and 54% of faculty were male, however, faculty <40 years old were predominantly women. The majority of both groups were white. Median bed count (n = 20) was similar in ICUs and multi-disciplinary paediatric ICUs. The median service expectation for one clinical full-time equivalent was 14 weeks of clinical service (interquartile range 12, 16), with the majority of programmes (86%) providing in-house attending night coverage. Work hours were high during service and non-service weeks with both directors (37%) and faculty (45%). Conclusions: Racial and ethnic diversity is markedly deficient in the paediatric cardiac critical care workforce. Although the majority of faculty are male, females make up the majority of the workforce younger than 40 years old. Work hours across all age groups and unit types are high both on- and off-service, with most units providing attending in-house night coverage.