Systems, devices, apparatuses, components, methods, and techniques for cadence and media content phase alignment are provided. An example media-playback device includes a content output device that operates to output media content, a cadence-acquiring device, a phase-delay calibration engine, a cadence-based media content selection engine, and a phase-aligned media playback engine. The cadence-acquiring device includes a movement-determining device and a cadence-determination engine configured to determine a cadence based on movement data captured by the movement-determining device. The phase-delay calibration engine configured to determine phase delay values for at least one cadence value. The cadence-based media content selection engine configured to identify a media content item based on the cadence determined by the cadence-acquiring device. The phase-aligned media playback engine configured to align the identified media content item to the repetitive-motion activity and cause the media-output device to output the aligned media content item.