He tells CBS News Correspondent Cynthia Bowers, "Honestly, after being shot in the head, I should be dead. And I'm not. I'm here. I'm a very happy man, believe me."
That's not to say his life didn't change beyond all measure. The bullet lodged in his spinal cord - leaving him paralyzed from the neck down, incapable of even breathing on his own. But he's still here and still working.
He says, "I'm still a father to my daughter Maggie, and I'm still a husband and I have a wonderful quality of life."
For him, everything is relative. And nothing is easy.
A respirator breathes for him every minute of every day. He requires around-the-clock nursing care. And he can only wonder how it would feel to hug his young daughter Maggie.
A lot of people consider Mullen a hero; to Maggie, he is special "in different ways than everybody else," she says.
But Mullen doesn't spend much time feeling sorry for himself. He's become a celebrity of sorts, as well as a vocal advocate for the disabled.
Mullen says, "Without a doubt, there's a valley between us. A lot of people are very uncomfortable around people who are disabled. I can provide a unique view from our side as to issues that affect us that you might not even consider. You always have that step and you can always lift your leg up to get over it. I don't have that luxury.
What he has is a voice and a brand new chance to send his message out to a much wider audience. He was hired as a reporter recently at WBBM television, the CBS station in Chicago, where he covers issues that hit close to home.
About his new job, Mullen says, "I'm very happy to be here and taking on a new role as, let us say, a liaison between the disabled community and non-disabled community."
He says he wasn't sure at first whether he wanted to take on all the extra work being a reporter would entail. After all, he already runs a business and a charitable foundation that helps the disabled. But then, he remembered what it's been like for him - trying to learn how best to live a life no one would ever imagine.
He notes, "There's been a lot of rough days, I'm not going to sit here and try to pretend that I was, you know, this pillar, or rock of Gibraltar all the time, because you do have bad days and wish things could be different some days."
But almost as soon as he says it, he moves on. Because, he says, he'd rather think about today and tomorrow, rather than dwell on the past, however tragic.
Mullen says, "At this point in my life, it's another crazy chapter. From being on death's doorstep, to now being a completely paralyzed quadriplegic, being a news reporter."
Asked if there is still a lot of life and laughter left? He replies, "Without a doubt! And many lobster tails left to be eaten."