Background A significant proportion of triptan users exhibit an insufficient response or inadequate tolerability to a triptan, and some may develop a contraindication. Lasmiditan, a selective 5-HT1F receptor agonist, may be an option for these individuals. We assessed lasmiditan efficacy in a subgroup of patients in CENTURION (Phase 3 migraine consistency study) who exhibited an insufficient response to triptans, including a subgroup with insufficient response due to efficacy only. Methods Patients were randomized to lasmiditan 200 mg for four attacks, lasmiditan 100 mg for four attacks, or placebo for three and lasmiditan 50 mg for one attack. Triptan insufficient responders were pre-defined as patients with insufficient efficacy or tolerability, or who developed a contraindication. Results In triptan insufficient responders, lasmiditan was superior to placebo (p < 0.05) for pain freedom beginning at 1 h (both doses); pain relief beginning at 0.5 (200 mg) or 1 h (100 mg); migraine-related disability freedom, much/very much better on the Patient Global Impression of Change, and most bothersome symptom freedom at 2 h; sustained pain freedom; and need for rescue medication. Lasmiditan showed benefit for consistency of effect across attacks for 2-h pain freedom and pain relief. Findings were similar in triptan responders and triptan naïve patients and when the triptan insufficient response definition was based on efficacy only. Conclusions Lasmiditan was efficacious across multiple clinically relevant endpoints in the acute treatment of migraine independent of prior response to triptans. Trial Registration: CENTURION (NCT03670810); SAMURAI (NCT02439320); SPARTAN (NCT02605174)