Former U.S. ambassador to Kenya Scott Gration told CNN Sunday that he perceives a double standard in his firing in 2012 for using a personal e-mail account while under then-Secretary of State Hillary Clinton, who, as it turns out, was doing the same thing.

During his appearance on State of the Union, Gration was described as one of the first high-profile policy endorsers of Barack Obama in 2008 and quickly became the top candidate to head NASA.

But in 2012, Gration was forced to resign from his post as ambassador in part because he used a personal e-mail account for government business. In the State Department's Inspector General Report, it was stated that there were "concerns with management and leadership" under Gration and that he had "lost the respect and confidence of the staff to lead the mission."

Now, Gration is finding it difficult to understand why his use of personal e-mail abruptly ended his career:

As I was going through [the firing], I did not perceive that it was a double standard because I did not know of Secretary Clinton's use of a commercial e-mail account. But as I've reflected on it over the last couple of days, it does appear like there was a different standard that was used in my case [than] that has been used in hers.

Clinton's chief of staff at the State Department, Cheryl Mills, was responsible for firing Gration. He believes Mills was aware of Clinton's private e-mail account. "I do find it sort of unusual that [Mills] stated that this was one of the reasons why I had to move on and as I look back, it seems a bit unfair," Gration said.

In the end, Gration, a retired Air Force general flying 274 combat missions in Iraq, described the abrupt end to his illustrious career while others continue in theirs:

For me, this is a dream job. It was a job where I felt I was making a significant difference in light of America's interests and what we were trying to do here -- to protect Americans. And to have that terminated over some allegations that were, in the end, proven to be false, and I was exonerated, and these claims were dismissed. And to see this dream job of mine come to an end was very disappointing to me. And to now find out that in reality, other people in the department, to include my supervisors, were doing things differently and were looking the other way, I think that's hard. I didn't break any laws willfully. If I made mistakes, I apologize for those, but I don't believe I did anything wrong and I can't speak the same for Secretary Clinton. Other people will have to make that decision. She'll have to work that out herself.