Low back pain affects millions of workers every year. From a preventive perspective, the use of passive exoskeletons is growing in the industrial field. The present study aims to evaluate the effects of a passive trunk exoskeleton on muscle activity and kinematics of the trunk and legs, displacement of the center of pressure, and perceived discomfort. 14 participants performed two tasks with and without exoskeleton. The first one was a lifting and lowering task and the second one was a static trunk flexion task at 40°. The results showed a significant reduction of approximately 18% in myoelectric activity of the erector spinae longissimus as well as a reduction in perceived discomfort in the thoracolumbar area on both tasks. The use of the exoskeleton increased external oblique activity by 28.6% during the load-bearing task, while leg muscles were not significantly impacted. The exoskeleton slightly impacted the kinematics of the trunk but leg kinematics were not, nor was postural balance. Given the study’s results, this device therefore seems to have the ability to reduce the risk of onset of low back pain at work.