In 1991, Kent State University student Michael Mould began translating Ruggero Leoncavallo's opera Pagliacci into English for a comics adaptation, but died on USAir Flight 405 before he could complete it.

Andreyko finished Mould's translation as The Clowns, a one-shot written by P. Craig Russell and illustrated by Galen Showman.

In 1997 he co-created (with Jay Geldhof and Galen Showman) The Lost, a Harvey-nominated comics mini-series which continued the story of Peter Pan in modern times, with the protagonist presented as an amoral vampiric boy prostitute.

Later work includes The Ferryman for Wildstorm, created by Joel Silver, with artist Jonathan Wayshak.

In 2011 he collaborated with artist Billy Tucci on a fill-in story for Birds of Prey, which featured his Manhunter character.