Kosmo Vinyl is mostly known (by me, anyway) for his work with the Clash. He served as their press agent during most of their career, as well as general dogsbody, drinking pal, road manager, "creative director", etc. Later, after they fired Bernie Rhodes, he would also become their manager.
Apart from his work with the Clash, he has also produced several bands, he runs the Casino Royale label, manages and produces a band called Jack Black, and he also featured in Martin Scorcese's King Of Comedy, along with the Clash, as a couple of street punks who harass Robert De Niro.