The present study investigated whether work engagement is related to and can explain healthy cardiac autonomic activity as indicated by decreased heart rate (HR; i.e., sympathetic and parasympathetic activity) and increased high-frequency power (HFP) of heart rate variability (i.e., parasympathetic activity). A total of 30 healthy Finnish female cleaning workers underwent an ambulatory monitoring period of two nights and two regular workdays, and mean values of work period HR and HFP were utilized as dependent variables. Correlations revealed that work engagement was, as hypothesized, negatively related to HR and positively to HFP. Furthermore, in hierarchical linear regression analysis, work engagement accounted for an additional 19% of the variance explained in HFP, independent of individual baseline, age, Body Mass Index, physical fitness, and medication. However, the explanation rate for HR did not reach statistical significance. The findings suggest that work engagement is associated with healthy, adaptable cardiac autonomic activity, particularly increased parasympathetic activity.