The objective was to examine employee engagement in worksite wellness activities at 2 large US companies that differed in engagement strategy and incentive plan. Inclusion criteria were US employees aged 18 to 65 who were eligible to receive wellness benefits throughout 2012. Company B's incentive was twice the dollar value of Company A's and produced higher engagement rates for the health assessment (HA; 26.1% vs. 24.4%, P<.001), and biometric screening (32.8% vs. 25.4%, P<.001). Among the subgroup of employees who completed the HA and the biometric screening, 44.6% (N=2,309) at Company A engaged in at least 1 coaching session compared to 8.9% (N=594) at Company B. Fewer employees at Company A with high-risk cholesterol engaged in coaching compared to Company B (44.6% vs. 54.9%, P=.009). However, more Company A employees with high-risk blood pressure engaged in coaching compared to Company B (41.3% vs. 34.8%, P=.053). Company A engaged more obese employees compared to Company B (43.7% vs. 13.9%, P<.001), although obesity was not directly targeted at either company. Predictors of enrolling in coaching included being female, older age, higher education, and those not at high risk for stress, diet, and tobacco for Company A, and older age, and high risk for blood pressure, cholesterol, and obesity for Company B. A population approach to incentive design for program engagement engaged high-risk employees in coaching, and engaged a high proportion of employees not at high risk, but who can still be at risk for chronic diseases. (Population Health Management 2014;17:324-331)