After a brief spell at Southern Television, he became well known as an in-vision announcer for Thames Television from 1976, also announcing during this period for ATV and HTV West, and presenting a weekend show on BBC Radio 2.
For a long period in the 1970s and 1980s he co-hosted the Miss United Kingdom beauty pageant with Judith Chalmers, and the Miss World beauty pageant (alongside Alexandra Bastedo on one occasion).
he was Arts Editor for HTV Wales and presented News & consumer shows.
In 1989, he also hosted the first UK revival of Sale of the Century, on the fledgling Sky TV satellite network.
Marshall worked as a radio presenter with the BBC, and spent several years as host of the evening show on Melody FM in London.