We provide experimental evidence of super-harmonic self-pulsation in a laser diode with a phase-conjugate optical feedback (PCF), i.e., time-periodic nearly sinusoidal oscillating output power at a frequency being multiple of the external-cavity frequency that corresponds to the long-standing predictions of so-called “external-cavity mode” [G. P. Agrawal and J. T. Klaus, Opt. Lett. 16, 1325–1327 (1991)]. High-harmonic self-pulsations have been so far limited to configurations with long time-delay, hence to relatively small frequencies (<1–2 GHz). By contrast, the reported self-pulsating solutions from PCF are stable in a larger range of feedback strength and with higher-order harmonic number when decreasing the external-cavity time-delay.