He was popularly known as Whispers after the name of the column he wrote for The Daily Nation from 1982 to 2003, offering a satirical view of the trials and tribulations of Kenyan life.
Mutahi was equally well known in theatre where he wrote and acted in English- and Kikuyu-language plays that caricatured Kenya's society and politics using his company Igiza Productions.
Among his books are Three Days on the Cross which won the Jomo Kenyatta Prize for Literature (1992), Jail Bugs, Doomsday, and How To Be a Kenyan, based on his newspaper columns.
He was charged with sedition and alleged association with the underground Mwakenya Movement and later transferred to Kamiti Maximum Security Prison.
In early 2003 Mutahi underwent what was supposed to be a routine, minor and painless operation at the Thika District Hospital to remove a lipoma from his back.
In addition, the Kenya Publishers Association started the bi-annual Wahome Mutahi award for literature, in his honour in 2005.