Rudolf grew up at Åsen farm, close to the working class districts of Sagene and Torshov.
When he was about 7–8 years old, he was the theatre director for Aasen Theater and instructed young actors in little plays he had written himself.
His first fictional work that was publicly well-known was the comedy Ole Høiland, which was written in 1883 and performed the same year at Møllergatens Theater.
In addition to Kristiania novels Muus later on wrote crime fiction and stories about rural districts.
On his 25th anniversary as a writer, he stated that the historical stories Ravn den fredløse and Olaf Trygvessøn were his favourites in his writing career up till that point.
Throughout his career he wrote under some 40 different names, including Sigmund Tofte, Bjørn Farmann, Gaston Ring, Rolf Ragnvaldsøn, Herman Brage, Spectator, Diogenes, Maximos and Rollo.
A normal fee for writers of fiction at the time was about 10-15 Norwegian kroner per 16 page piece, regardless of the size of circulation.
The majority of the profits from Muus’ books and booklets fell into the hands of the publishing companies.
Though it was not mentioned in the opening credits, the movie Trysil-Knut was based on Muus’ book about the skilled cross-country skier.