Done Need help with a sentence...

[Guren no heya kara]

Hello again.
Context: a little boy (very bad at sports, very good at studying) is talking about his
twin brother (very good at sports, very bad at studying...the opposite, basically).

ちょっと運動ができるからって
学校じゃいい顔させないよ。

What does いい顔させない stand for?

 

[Aarowaim]

ちょっと運動ができるからって
学校じゃいい顔させないよ。

Roughly: "He doesn't like school because he 'has to sit around'"

いい顔 is like 'to be happy', or have a smile.
いい顔(を)させない means school doesn't allow him to be happy

The twin brother explains that his sportier brother doesn't like school -- quoting his brother's reason -- 'because (he) can only exercise/move a little bit'

 

[Guren no heya kara]

...are you really sure?
I intended it as

Even if/Just because he's a little good at physical stuff,
that doesn't make him the boss of the school.

いい顔 as big-shot, influential person;

He's very lively, a little pest, plays pranks on teachers,
disturbs classes, makes witty remarks... Always drags
around his twin, who, poor guy, is tired just by running
5 minutes and would like to do quietier stuff...like
reading books, chatting...

You think that this って quotes the other twin motive then.
Hmm...

 

[Utsune]

I would go with the "You don't become a big shot at school just being good at sports" perhaps?

edit: or just simply 'become successful'

 

[mikkih]

How about something like....I'm not gonna let you act cool/become popular at school just because you're athletic.

 

[Guren no heya kara]

...So none of you has got an idea about what that sentence really mean
Just kidding, you helped me make a decision and that's really appreciated

 

[mikkih]

...So none of you has got an idea about what that sentence really mean
Just kidding, you helped me make a decision and that's really appreciated

Perhaps I forgot to add the lireral translation, which you could use.

I'm not gonna let you present yourself well at school just because you're (or just being) athletic.

いい顔させない = "not allow (someone) to present (one)self well."