In 1966, Dusty Springfield approached Napier-Bell and Vicki Wickham to write an English lyric to an Italian song she had heard at the Sanremo Festival, composed by Pino Donaggio. The result was “You Don’t Have to Say You Love Me”, which became Springfield’s only number one hit in the UK Singles Chart.

Following this, he worked in Spain and South America for two years, managing one of Spain’s biggest stars, Júnior, with whom he co-wrote several Spanish hits, in particular the biggest selling Spanish language single of the 1970s, “Perdóname”. In 1976, he came back to London and returned to management with two new groups, London, a group in the then current punk vein, and Japan, an art-rock group. London was a short-lived project (two national tours, two singles, a 4-track EP and an album for MCA Records) but Japan involved him for the next seven years. Napier-Bell persevered with them through five lean years to eventually help make them one of the most influential groups of the early 1980s.

Napier-Bell then established an association with manager Jazz Summers and together they took on the management of Wham!. The group had previously had three hit singles in the UK but wanted to terminate their contract with the record company, Innervision. Napier-Bell and Summers led them through four months of legal complications (during which they were unable to record), and finally settled the case by signing a new contract with CBS. Napier-Bell spent eighteen months travelling backwards and forwards to China negotiating for Wham! to become the first ever Western pop artist to play in communist China. They eventually played a concert there in April 1985 at the Worker’s Stadium in Beijing.

When Japan broke up, Napier-Bell wrote his first book, You Don’t Have To Say You Love Me, about his experiences in the music business in the 1960s. When he ceased managing Asia and Ultravox he wrote another book, Black Vinyl White Powder, about the British music business which was received with favourable reviews. In March 2005, he published another book, I’m Coming To Take You To Lunch, the story of how he took Wham! to China.

Following this, Napier-Bell collaborated with another manager, Harry Cowell, and they took on the management of two once major groups looking to revive their careers – Asia and Ultravox. Asia fared better than Ultravox, but eventually Napier-Bell gave up on both of them and spent three years writing a book, Black Vinyl White Powder. He returned to artist management, this time working in Russia, first managing Alsou, a girl singer, then Smash!!, a boy duo with Wham! similarities In 2013, he joined forces with Dutch entrepreneur Björn de Water by setting up Snap-B Music Ltd, a music consultancy company offering advice to artist managers. Napier-Bell terminated his directorship of the company in 2016 but remains a consultant.

In 2015, Unbound Books published his fourth book, Ta-Ra-Ra-Boom-De-Ay, which is a complete history of the music industry since the early 18th Century until today. All four books have received multiple reviews.