Wiacek got his start in the mid-1970s as a member of the "Crusty Bunkers" inking collective. For a short time in 1975–1976 he inked backgrounds (over Curt Swan's pencils) on Superman for DC Comics. He moved on to regular inking work for DC, and then in 1978 began a long association with Marvel which lasted until 1993.
Wiacek's first regular title was on Man-Thing issues #1-11, from 1979 to 1981, where he inked over Jim Mooney's pencils and then provided finished art based on Don Perlin's breakdowns. During this same period, Wiacek was the regular inker on Marvel's Star Wars comic, issues #16-37, working with Carmine Infantino.
In 1981, Wiacek moved on to be the regular inker on Uncanny X-Men, primarily inking Paul Smith in issues #159–176. Wiacek's next regular stint was John Byrne's inker on Alpha Flight, issues #15-29 in 1984–1985. Overlapping with that job was Wiacek's work as inker for June BrigmanonPower Pack issues #1-26.
In the years 1986–1989, Wiacek was the primary inker on X-Factor, issues #10-37, working with Walt Simonson. Wiacek then moved on to Sensational She-Hulk #1-11, reuniting with John Byrne for much of that period.
From 1990 to 1992, Wiacek embarked on his longest stretch as an inker, working with John Romita Jr. and then Bob LaytononIron Man issues #258–283.
Wiacek's last long-term inking stint was on DC Comics' Orion, inking over Walt Simonson's pencils for issues #8-22, from 2001 to 2002.
Over the years, Wiacek has also inked comics published by Dark Horse and Valiant.
