[3] Nagao competed at two major international events that year: he was Asia's selection for the 1977 IAAF World Cup, placing eighth,[4] and was a bronze medallist at the 1977 Pacific Conference Games, finishing behind Australian Garry Brown and Sam Turner of the United States.

He reached the final and finished in a time of 50.98 seconds, taking runner-up spot behind Iraqi hurdler Hussein Kadhum.

[6] He teamed up for the 4×400 metres relay with sprinters Eiji Natori, Yasuhiro Harada and long jumper Junichi Usui and anchored the quartet to a gold medal, narrowly holding off India's 800 m Asian Games champion Sri Ram Singh.

[7] Nagao ran a lifetime best of 49.59 seconds in Tokyo in September that year – a time which placed him eleventh on the global seasonal rankings.

[3] Replacing Kadhum as the region's top hurdler, he was chosen for both the 400 m hurdles and the 4 × 400 m relay team for Asia at the 1981 IAAF World Cup.