Jiří Petráček was born in Prague, and graduated from the Václav Hollar Art School in 1959. He has worked as a freelance artist from 1971 until his retirement in 2002. His first comic work was 'Expedice Yeti' in 1971, and was signed Pet Dudwöl (a joint signature for the authors Petráček, Oldřich Dudek and Otakar Volšička). He has also illustrated many educational textbooks, especially about Czech history.
He was a contributor to Sedmička pionýrů from 1979, where he created the comic series 'Třináctka ze Staré čtvrti' ('Thirteen of the Old Quarter') with Pavel Toufar from 1981 to 1984 and 'Mimozemšťané' ('Extratrestrials') with Jiljí Záruba from 1984 to 1988. He was subsequently a contributor to ABC with 'Gulliver', 'Golem', 'Návrat z ráje', 'Nebe v plamenech', 'Divoký Dick' or 'Pán jaguárů', all in cooperation with either Rudolf Baudis or Václav Šorel.
He additionally made 'Clovek zvaný Son' with Ivo Pehchar and 'Kamarádi z prérie' with Pavel Kosatík and Magda Ziková for the Knizní Podnikatelský Klub (Business Book Club) in 1990 and 1991. Petracek and Pechar also worked together on six mini-comics in the 'Stopar' ('Hitchhiker') series for Pressfoto. Following the Velvet Revolution in 1989, Petracek was also present in Kometa magazine.