She is a popular guest at science fiction conventions, and she can often be seen at the large filksings with her distinctive 12-string guitar, "Monster", which Leslie says plays best when it is given good Scotch whisky.

Fish has been involved with numerous political causes, most notably anti-war activism during the Vietnam War, and is a longtime member of the Industrial Workers of the World, a fact referred to in several of her songs (e.g., "Wobblies from Space", "Leslie's Filks").

She is also well known as a gun-rights activist, and has asserted that private gun ownership is the only true protection of individual freedom (a topic touched on in several of her songs).

Her album Firestorm was in large part meant as a set of instructions for surviving a nuclear war, on the reasoning that it would be easier to recall them if they were in lyric form.

In Textual Poachers, a landmark study of fan communities, MIT's Henry Jenkins described Fish's anarchist-feminist Star Trek novel The Weight as a 'compelling narrative' 'remarkable in the scope and complexity of its conception, the precision of its execution, and the explicitness of its political orientation.

Since 2007,[14] she has been the driving force behind the establishment of Fan Haven, a 230-acre (93 ha) private park in Arizona meant to serve as a safe space for LARPers, Pagans, naturists, SCAdians, and other marginalized groups associated with fandom.

[citation needed] While Fish rarely discusses her private life, she was in a romantic relationship with anarchist political activist Mary Frohman "from the late '60s through the early '80s.

The following short stories appeared in the War World series, a shared universe created by Jerry Pournelle:[22] Writing as F. Sigmund Mead, "A Summary of the Physiological Roots of Andorian Culture" (Journal of Xenoanthropology, June 2341), edited by Leslie Fish.