He studied at the Escuela Nacional Preparatoria nNumber 1.

Since it's a name, I made it capital.

He became an excellent teacher who gave his life for education.

I learnt a bit about his perspective,; for example, he believed that the end doesn't justify the means, and that school must be a mirror of how we want our society to be.

It was about a Mexican philosopher callnamed Antonio Caso.

“Named” is more accurate usage here. Your text is factual and thus informative in nature, it states, it handles facts and opinions with an objective tone. I would stay formal with “named”.

Correct/common examples of “called”: “She had a boy called Steve.” “He was a boy called Steve.” “She called the dog by its name.” More for casual writing conventions.

He became an excellent teacher who gave his life for education.

A becomes a before nouns beginning with: a, e, i, o or u.

I learnt about his perspectives, for example, he believed that the end doesn't justify the means, and that school must be a mirror of how we want our society to be.

If you are writing “for example”, you automatically imply that there is more than one potential option. Therefore, perspective should be a plural to represent this fact.

He studied at the Escuela Nacional Preparatoria number 1 and wanted to become a philosopher even though he studied law.

Although these sentences are grammatically correct, repeating the same sentence structure can be boring. Try combining sentences.

He wanted to become a philosopher even though he studied law.

He became an excellent teacher who gave his life for education.

I learnted about his perspective, for example, he believed that the end doesn't justify the means, and that school must be a mirror of how we want our society to be.

"learned' is American English, while "learnt" is British. Make sure you're consistent with which English you're using.

Furthermore, he was part of a conference group called, "El aAteneo de la jJuventud"."

Punctuation & capitalization

He became an excellent teacher who gave his life for education.

I learnted about his perspective, f. For example, he believed that the end doesn't justify the means, and that school must be a mirror of how we want our society to be.

Furthermore, he was part of a conference group called, " El aAteneo de la jJuventud".

He studied at the Escuela Nacional Preparatoria number 1.

numero uno maybe? haha

He became an excellent teacher who gave his life forto education.

Or even better, "dedicated his life to education."

I learnted about his perspective, f. For example, he believed that the end doesn't justify the means, and that school must be ashould mirror of how we want our society to be.

"Learned" is used more commonly, at least in America.
Second part if fine, but it sounds better this way.