After a massive deadly zombie attack, a brave and honorable, brought back to life, police officer wants to save his town and citizens from the bloody carnivores. He goes towards achieving his goal in order to kill the last zombie leader and become “alive” again.

Possible title: Medal of Horror

"When he returns as a zombie, a formerly dead, medal of honor winner chooses to fight against his new brain eating brethren, in order to defeat the evil that's creating the undead apocalypse."

That's definitely an improvement on the first version.
Here's a quick fix for you to keep working with:
After a zombie attack,? a sheriff must kill the zombie leader to save his town from an outbreak.

If it's an outright zombie apocalypse instead of a local outbreak, there's hardly much a cop can do short of building a wall around the town to keep the zombies out.

Other than that, this comes across as a straight up zombie genre film, how is it going to stand out from the many that have been, are, and will be made?

"After a zombie attack,? a cop must kill a zombie leader to save town from the "apocalypse"

Is this a little bit better?

The wording in this logline confuses me.

"...He goes towards achieving his goal in order to kill the last zombie leader and become ?alive? again..." - What does go towards achieving his goal mean? Where does he go? Do you mean he makes an effort/fight to achieve his goal? If so, there's no need to literally spell that out as it's the very basic definition of a protagonist.
According to this clause, the goal is a prerequisite objective to killing the zombie leader, but don't you mean that his goal is to kill the zombie leader? And who does? "...become ?alive? again..." refer to? Him? Is he dead? If so, how is he able to do anything? Do you mean to say he is a zombie as well? If so, how is he able to function?

I get that you've formulated your own type of zombie flick with rules that make your plot work. However, the rules of this genre are so widely known that most people would likely not rationalise your set of rules against what they know already and will therefore not be able to make sense of your premise first up. If you decide to write within a genre, you need to respect the rules and conventions of that genre.

"...save his town and citizens..." - They aren't his citizens, they're the town's. Just write that he wants to save the town, it's implicitly clear that he wants to save the people who live in it.

"...a brave and honorable, brought back to life, police officer..." - which of these descriptions is the most relevant to the plot? Keep only that and cut the rest.

"...a massive deadly zombie attack..." - just write a zombie attack, the adjectives are redundant.

In addition to many redundant descriptions, there's too much about this logline that doesn't make sense. Clarity is vitally important in a logline, and your explanations of exactly how all these pieces work together in this particular take on the genre will likely come across more as convenience writing than anything else.