Kirk Cameron insists that before his conversion he was a die hard atheist. I don't really believe his classification for a second.
None of the infamous Neo-atheists who are responsible for the "faith" becoming so...radical were relevant when he was converted, though.
I understand this. I'm just saying that I think he very likely exaggerates how much of a die hard atheist he was before his conversion, because it makes the story more dramatic.
Being openly atheist at all basically implies being a "die-hard atheist" at the time.
Remember, religion didn't decline much until post-Cold War so during Cameron's time the level of "No religion" people was much lower than it is now and as such, other people would likely call you a "die-hard atheist" if you said something non-religious.
These days, in liberal Internet circles like the Young Turks, being non-religious is practically a badge of honor.