Acquired brain injury (ABI) can lead to a constellation of higher-order executive problems, which can impact significantly on everyday behaviour. While some neuropsychological assessments are able to measure these impairments objectively, increasingly, clinicians are finding that a subset of their patients passes these tests while still exhibiting difficulties in day-to-day living. Calls have therefore been made to develop assessments that are more sensitive and that are more ecologically valid. In this study, in Experiment 1, a multiple errands task (MET) based around a business office was created to assess concurrently nine aspects of executive functioning (planning, prioritisation, selective-thinking, creative-thinking, adaptive-thinking, multi-tasking, action-based prospective memory (PM), event-based PM and time-based PM). This new paradigm, the Jansari assessment of Executive Functions (JEF©) showed a significant difference between six individuals with ABI and matched healthy controls; further, it showed that across the nine constructs there was a range of performance. In Experiment 2, JEF© was recreated in a virtual environment resembling a computer game, and it was found that this version significantly differentiated between 17 individuals with ABI and 30 healthy controls. These results suggest that the virtual version of JEF© could be used as a new assessment of executive function. The profile of performance across the nine constructs for each individual provides a wealth of objective information that could potentially inform targeted rehabilitation.