**Abstract** **Background**: Current research on healthcare workforce focuses on burnout and its consequences. This study examines whether workforce well-being, specifically engagement, promotes organizational performance. **Methods**: We measured workforce engagement with three questions from the National Health Services (NHS) [Staff Surveys](https://www.nhsstaffsurveys.com) corresponding to three validated factors by the UWES-9 survey: vigor, absorption, and dedication. Organizational performance was measured by the summary [Hospital-level Mortality Indicator (SHMI)](https://digital.nhs.uk), available for all English hospital Trusts from 2012 to 2018. In the first analysis, SHMI was the dependent variable, predicted by engagement measured in the prior year, current year, and year following SHMI measurement while controlling for SMHI in the prior year. For the second analysis, the associations of the SHMI with engagement were examined in both directions using [previously published][1], cross-lagged regression methodology. The lag duration was identified based on results of the first analysis. Year 2017 was analyzed in depth using meta-analysis to measure heterogeneity in workforce engagement across Trusts. **Results**: Participating Trusts and average number of staff responses per Trust varied from 141 and 398, respectively, in 2012 to 130 and 2423 in 2018. The average staff response rate, reported from 2014-2018, was 45% (range: 43.5% to 46.6%). Pooling data for all years, Trust SHMI ranged between 0.9996 and 1.0044, and engagement score range, 3.83 to 3.94, with no significant differences by year in the median SHMI or engagement scores. Detailed analysis of 2017 data showed high inter-Trust heterogeneity on all three engagement factors (I2 > 85%). In the first analysis, using pooled data for 2013 through 2017, current SHMI was negatively associated with both current engagement (ß =-0.05; p = 0.041), engagement in the ensuing year (ß = -0.07; p = 0.006), but not with engagement in the prior year. In the second analysis: a) Engagement predicted same-year SHMI after controlling for prior year SHMI (ß =-0.04; p = 0.040) and 2) SHMI predicted engagement in the same year (ß =-0.07; p = 0.001) after controlling for prior-year engagement. **Conclusion**: Our finding, using current NHS human resource data, that higher workforce engagement predicts lower mortality confirms prior findings of real-time association between engagement and performance. Our finding that current SHMI also predicts current engagement is a new finding and suggests that good organizational performance increases engagement and vice versa. Future research should examine whether workforce states that build on engagement, such as thriving, which includes workforce learning, improves prediction of SHMI. The considerable heterogeneity in rates of workforce well-being suggests opportunity to foster mutual learning across Trusts. **Source files at original websites** - Mortality data at [digital.nhs.uk][2] - Care Quality Commission (CQC) ratings from [www.cqc.org.uk][3] - Adult Inpatient Surveys from [www.nhssurveys.org][4] - Staff Surveys results at [www.nhsstaffsurveys.com][5] [1]: http://pubmed.gov/18361647 [2]: https://digital.nhs.uk/data-and-information/publications/clinical-indicators/shmi/ [3]: https://www.cqc.org.uk/what-we-do/how-we-do-our-job/ratings [4]: http://www.nhssurveys.org/previoussurveys [5]: https://www.nhsstaffsurveys.com/Page/1021/Past-Results/Historical-Staff-Survey-Results/