"One day I was just looking at the coins (that) is what brought this up," Michael Newdow told CNN television. "I saw 'In God We Trust' on my coins. I said, 'I don't trust in God,' what is this?
"And I recalled there was something in the Constitution that said you're not allowed to do that and so I did some research. And as soon as I did the research, I realized the law seemed to be on my side and I filed the suit.
"It's a cool thing to do. Everyone should try it," he said.
The decision, reached by the 9th Circuit Court of Appeals, overturned the 1954 act of Congress that inserted the phrase into the Pledge of Allegiance and immediately set off a firestorm. President Bush condemned the move, as did members of Congress, who gathered on Capitol Hill Thursday to recite the pledge together.
The fruit of his labor, however, is delayed. On Thursday, Judge Alfred T. Goodwin, who wrote the court's opinion, stayed the decision for 45 days to allow court challenges.
The cooling off period would also give the three-judge panel time to weigh changing their ruling.
Newdow, a physician with a law degree, represented himself in the appeals court case, arguing that reference to God in the Pledge of Allegiance was unconstitutional because it violated the doctrine of separation of church and state.
The lawsuit was filed on behalf of his elementary school daughter, he said, although she was not required to say the pledge in school, nor was she ostracized by her classmates for not doing so.
"My daughter is in the lawsuit because you need that for standing," he said in the television interview. "I brought this case because I am an atheist and this offends me, and I have the right to bring up my daughter without God being imposed into her life by her schoolteachers. So she did not come and say she was ostracized."
Newdow, who said he was pleased with the court decision, said he intends to keep fighting to remove references to God from government, including from U.S. currency.
"This issue is whether or not our government should be infusing religion into (schools). Our churches are very strong in this nation and I think that's great and everybody should have the ability to worship as he or she sees fit. I choose to worship not believing in God and government should not thrust a religious idea down my throat," he said.