There is a growing need to understand the association and interaction of psychological factors with an athlete’s competitive standard and mental well-being. John Henryism is defined as a coping mechanism that involves the expenditure of extreme efforts in response to prolonged exposure to psychosocial and environmental stressors. The aim of this study was to investigate whether John Henryism, fear of failure and the John Henryism × fear of failure interaction (JH×FF) could predict an athlete’s competitive standard, as well as mental well-being. A cross-sectional design was employed; 250 athletes (52% male, 48% female, Mage= 29.36 years) completed an online questionnaire. Hypotheses were partly supported. Results revealed that John Henryism predicted an athlete’s competitive standard, with individuals reporting high John Henryism more likely to compete at an international level than a regional, third tier or national level. Fear of failure was only significant in distinguishing national and international level athletes, with those reporting high fear of failure more likely to compete at a national level. JH×FF did not predict an athlete’s competitive standard. Further, John Henryism and fear of failure predicted mental well-being, but JH×FF did not. Specifically, while fear of failure negatively predicted mental well-being, as expected, John Henryism positively predicted mental well-being, contradicting expectations that factors aiding competitive standard are likely to deter mental well-being. Given these findings, future research should evaluate if interventions aimed at easing fear of failure or encouraging more active coping (i.e., John Henryism) benefit the well-being of athletes competing nationally or internationally. © 2022 International Society of Sport Psychology.