Background We aimed to assess the effects of preventive migraine treatment with atogepant vs. placebo on patient-reported quality of life and functioning. Methods Analyses of patient-reported outcomes from three 12-week, randomized, placebo-controlled trials evaluating preventive migraine treatment with atogepant 60 mg once-daily: ADVANCE (low-frequency episodic migraine [LFEM], 4–8 monthly migraine days [MMDs] and high-frequency episodic migraine [HFEM], 8–14 MMDs), PROGRESS (chronic migraine, CM) and ELEVATE (episodic migraine in those previously failed by two to four classes of oral preventive treatments). Results Least squares mean differences (95% confidence interval (CI)) in change from baseline were greater ( p < 0.05) for atogepant vs. placebo for Migraine-Specific Quality of Life questionnaire Role Function–Restrictive domain scores at week 12 (ADVANCE: LFEM 12.0 (95% CI = 6.0–18.0), HFEM 9.9 (95% CI = 3.4–16.4); PROGRESS: 6.2 (95% CI = 2.5–9.8); ELEVATE: 17.7 (95% CI = 13.1–22.3)), for Headache Impact Test-6 total scores at week 12 (ADVANCE: LFEM −4.7 (95% CI = −6.7 to −2.7); HFEM −3.4 (95% CI = −5.5 to −1.2); PROGRESS: −2.8 (95% CI = −4.1 to −1.4); ELEVATE: −6.5 (95% CI = −8.3 to −4.7)) and for Activity Impairment in Migraine–Diary-Performance of Daily Activities scores across 12 weeks (ADVANCE: LFEM −2.3 (95% CI = −3.9 to −0.7), HFEM −4.5 (95% CI = −6.9 to −2.2); PROGRESS: −3.4 (95% CI = −5.3 to −1.5); ELEVATE: −4.7 (95% CI = −6.4 to −3.1)). Conclusions Preventive migraine treatment with atogepant 60 mg once-daily vs. placebo improved measures of migraine-related quality of life and functioning among participants with different headache frequencies and histories of previous treatment failure. Trial Registration: ClinicalTrials.gov: NCT03777059 (ADVANCE); NCT03855137 (PROGRESS); NCT04740827 (ELEVATE)