Slartibartfast is a Magrathean, and a designer of planets.[2] His favourite part of the job is creating coastlines, the most notable of which are the fjords found on the coast of Norway on planet Earth,[3] for which he wins an award. While trapped on prehistoric Earth, Arthur Dent and Ford Prefect see Slartibartfast's signature deep inside a glacier in ancient Norway.

When Earth Mk. II is being made, Slartibartfast is assigned to the continent of Africa. He is unhappy about this because he wants to make more fjords (arguing that they give a continent a baroque feel), and fjords in Africa would be hard for him to explain without natural glacial movement.

In any event, the new Earth is not required and, much to Slartibartfast's disgust, its owners suggested that he take a quick skiing holiday on his glaciers before dismantling them.

Slartibartfast later joined the Campaign for Real Time (or CamTim as the volunteers casually refer to it, a reference to CAMRA) which tries to preserve events as they happened before time travelling was invented. He picks up Arthur and Ford from Lord's Cricket Ground with his Starship Bistromath, after which they head out to stop the robots of Krikkit from bringing together the pieces of the Wikkit Gate.

When he first meets Arthur, Slartibartfast imparts the following wisdom on life:

Slartibartfast: "Perhaps I'm old and tired, but I think that the chances of finding out what's actually going on are so absurdly remote that the only thing to do is to say, 'Hang the sense of it,' and keep yourself busy. I'd much rather be happy than right any day."
Arthur: "And are you?"
Slartibartfast: "Ah, no. (laughs) Well, that's where it all falls down, of course."