The purpose of this study was to examine the time course of health, fitness, and occupational performance changes in firefighter recruits across a fire academy. Nineteen recruits (24.9 ± 4.3 yr; 26.7 ± 3.1 kg·m -2 ) had their body composition, balance, vertical jump (VJ) performance, cardiorespiratory fitness (CRF), upper and lower body strength, hamstrings-to-quadriceps (H/Q) ratio, lower back endurance, and weighted stair climb (SC) performance assessed at the beginning (week 1 [W1]), midpoint (week 15 [W15]), and end (week 30 [W30]) of a fire academy. The fire academy improved body composition, balance, CRF, leg extension strength, and SC performance from W1 to W15 ( P ≤ 0.042) which then plateaued at W30 ( P ≥ 0.314). Leg flexion strength and the H/Q ratio decreased from W1 to W15 ( P ≤ 0.035) and plateaued at W30 ( P ≥ 0.947). Upper body strength was similar at W1 and W15 ( P ≥ 0.999), but decreased at W30 ( P ≤ 0.033). However, no significant changes occurred across the academy for VJ performance or lower back endurance ( P ≥ 0.090). These findings highlight the positive effect of the academy on body composition, CRF, balance, SC performance, and leg extension strength. However, the decreases in upper body and leg flexion strength, the H/Q ratio, and lack of changes in VJ performance and low back endurance may highlight key areas of need to maximize injury prevention and performance enhancement efforts in the academy. Further, the varied time course of changes may help fire departments identify opportunities to modify exercise programming across their academies.