Over these two decades, there have been many literature discussing the relationship between smoking and employment. Most found a higher prevalence of smoking among the unemployed. Some found being unemployed could increase the intensity of smoking and the probability of being a smoker. Few study the association between being a current or former smoker and employment. In particular, there hasn’t been a causal study regarding how being a current or former smoker could affect employment. This paper uses the trivariate probit model with instrumental variables, the prevalence of smoking by each state, seatbelt use and the maximal oxygen uptake, to estimate the causal effect of smoking status on employment and to take the potential endogeneity into account. After examining the data from 2017 Behavioral Risk Factor Surveillance System, an annual health-related telephone surveys conducted in all 50 states in U.S, we found being a current smoker would lead to a 0.14 percentage point deduction of the probability of being employed for females and 0.07 for males compared to those who never smoke. Another contribution of the paper is that we found that for a female observation to be a former smoker would increase the probability of being employed by 0.05 percentage points compared to those who never smoke while for male there’s no significant impact. To the best of our knowledge, the causal effects mentioned above have not yet been documented before. Also, our results suggest there do exist endogeneity between smoking status and employment. Therefore, the using of trivariate probit model with instrumental variables is desirable. Following our analysis, considering being a current smoker’s negative impact on employment for both females and males, the benefit on employment of females being a former smoker is important from the cost-benefit perspective of the smoking cessation policy.