Objectives: This study investigates the effects of 600 mg/day Ashwagandha root extract on physiological stress biomarkers, perception of recovery, muscle strength and aerobic capacity in team sports athletes during pre-season training, a period associated with elevated cortisol and accumulated training stress. Methods: Fifty-six athletes (26.8 ± 4.4 years, 1.74 ± 0.10 m, 79.4 ± 17.3 kg, 11.0 ± 7.1 career years) across rugby, water polo and football were randomly assigned to an Ashwagandha (ASH; n = 28, 14 males and 14 females) or placebo (PLA; n = 28, 14 males and 14 females) group for 42 days. Salivary biomarkers were assessed after training, muscle strength and aerobic capacity were measured during training, and perception of recovery was evaluated with Hooper Index (HI) the following day. Mixed ANOVA was used to determine group × time interactions and Bonferroni post hoc analyses were conducted for multiple pairwise comparisons. Results: In female athletes, salivary cortisol increased significantly in PLA (p = 0.001), while recovery parameters such as the overall HI score (p = 0.001), Delayed Onset Muscle Soreness (DOMS) (p = 0.008) and perception of fatigue (p = 0.026) scores improved significantly in ASH. In males, salivary cortisone increased significantly in PLA (p = 0.022), while Countermovement Jump (CMJ) improved significantly in ASH (p = 0.018). Pull-up performance increased in both PLA (p = 0.004) and ASH (p < 0.0001) in males. Conclusions: Supplementation with 600 mg/day of Ashwagandha root extract for 42 days may stabilise stress biomarkers, improve perception of recovery and enhance muscle strength in team sports athletes during pre-season training. The trial is registered on ClinicalTrials.gov with the ID NCT07041853.