Molly Fitzgerald's father was a fanatically militant Irish nationalist. When Molly was three years old, her father took her and her brother to the north Ireland mountainside as he asked the heavens to grant his son the power to strike down its enemies. Although nothing seemed to have happened, Molly found in her freshman year in college that she was the one who was blessed. She discovered she was surrounded with a protective aura that caused random improbabilities to manifest themselves on her behalf whenever she was in trouble. Rather than return to the war-torn mountains, she used her "good luck powers" to become Ireland's super heroine, Shamrock.
Fitzgerald's career as Shamrock remains largely unrevealed. At one point, she was transported alongside various other international heroes by the alien Grandmaster in order to participate in a so-called Contest of Champions, but she returned at the end of the encounter. Eventually, Fitzgerald began a career as a first-grade schoolteacher and abandoned her superhero activities in favor of building a better world through education.
When Molly's brother was killed in an IRA terrorist bomb blast, her father, long since estranged, asked her to come with him to the north Ireland mountainside once more. There, he drugged her and gave her to the criminal geneticist Arnim Zola in hopes that the mad scientist could duplicate Molly's powers and transfer them to her father. The process unleashed Molly's powers a thousand-fold, allowing her to escape, and Molly soon defeated Arnim Zola. Her father confronted her at gunpoint, frustrated that Molly would not use her powers in his militant quest. Unfortunately, Molly's powers defended her by making her father's gun explode in his hand, killing him. Molly Fitzgerald reluctantly returned to her former life and, presumably, her superhero career.
Molly, as Shamrock, attended the first ever Pan-European Conference on Super-Human Affairs as a representative for Ireland. The conference was attacked by the Nazi villain Brain Drain, who brainwashed the heroes present to return to their countries and kill the heads of state. Various members of Alpha Flight raced to stop the heroes, and Northstar hoped to stop Shamrock from attacking Ireland's president. However, her powers made her immune to Brain Drain’s influence, and the president was never in danger.
Molly finally took the opportunity to retire from crime fighting when she noticed her luck powers had finally run out-- she actually slipped and broke her left foot! She took up a new career as a hair stylist, soon becoming "the most sought-after hairdresser in all of Europe" and serving the likes of Shadowcat and Wolfsbane and Janet van Dyne.