This study aimed to evaluate the effect of a multimodal supervised exercise training (SET) program on walking performance for 12 months in patients with symptomatic lower extremity peripheral artery disease (PAD). Consecutive patients with Fontaine stage II PAD participating in the SET program of our hospital were retrospectively investigated. Walking performance, assessed using a treadmill with measures of the pain-free and maximal walking distance (PFWD, MWD, respectively), and 6 min walking distance (6MWD), were tested before and following SET, as well as at 6 and 12 months after SET completion. Ninety-three symptomatic patients with PAD (65.0 ± 1.1 y) were included in the study. Following SET, the walking performance significantly improved (PFWD: +145%, p ≤ 0.001; MWD: +97%, p ≤ 0.001; 6MWD: +15%, p ≤ 0.001). At 6 months, PFWD (+257%, p ≤ 0.001), MWD (+132%, p ≤ 0.001), and 6MWD (+11%, p ≤ 0.001) remained significantly improved compared with the pre-SET condition. At 12 months, PFWD (+272%, p ≤ 0.001), MWD (+130%, p ≤ 0.001), and 6MWD (+11%, p ≤ 0.001) remained significantly improved compared with the pre-training condition. The walking performance remained significantly improved in both women and men for up to 12 months (p ≤ 0.001). Multimodal SET is effective at improving walking performance in symptomatic patients with PAD, with improvements lasting up to 12 months.