Con el papel protagonista, el actor puede sobreactuar.

Not just literally with.

In this sentence, con el papel protagonista means something like:

• with the leading role
• when he has the leading role
• in the leading role

So con introduces the circumstance or situation under which the actor might overact.

A very literal English translation with with is possible, but the idea is really closer to given the lead role or in the lead role.

El is used because the sentence refers to a specific role: the leading role.

Compare:

• con el papel protagonista = with the leading role / with that lead role
• con un papel protagonista = with a leading role / with some lead role

In your sentence, el sounds more natural if the role is already understood or being referred to as a definite, identifiable role.

Yes, papel protagonista is understandable, but many speakers would also use:

• papel principal = main role
• papel de protagonista = role of the protagonist

The differences are slight:

• papel principal often sounds the most neutral and natural.
• papel de protagonista stresses that the character is the protagonist.
• papel protagonista is compact and understandable, but depending on context, it may sound a bit less common than papel principal.

So the sentence works, but a learner should know there are other very common ways to express the same idea.

Here protagonista is functioning like a descriptive word for papel, so yes, it behaves adjectivally in this expression.

Spanish often places descriptive words after the noun, so:

• papel protagonista
• papel principal

This is normal Spanish word order.

You should also know that protagonista is a word that can be both masculine and feminine depending on the person:

• el protagonista
• la protagonista

But in papel protagonista, it is describing papel, not directly naming a person.

Because protagonista is one of those Spanish words whose form often stays the same for masculine and feminine.

For people:

• el protagonista
• la protagonista

Same form, different article.

In your sentence, it is attached to papel, and the form remains protagonista. If you made it plural, you would normally get:

• papeles protagonistas

So the singular form here is completely normal.

The comma marks con el papel protagonista as an introductory phrase.

It helps separate:

• the setting or circumstance: Con el papel protagonista
• the main clause: el actor puede sobreactuar

This is very natural in writing when the speaker wants a slight pause or wants to frame the sentence before giving the main statement.

Without the comma, the sentence is still understandable, but the version with the comma is clearer and more polished.

Yes, Spanish often drops subject pronouns and even nouns when the subject is already clear from context.

So in the right context, you could say simply:

• Con el papel protagonista, puede sobreactuar.

But if there is no previous context, that sounds incomplete because we do not know who puede sobreactuar refers to.

Including el actor makes the sentence self-contained and clear.

Yes. El actor normally refers to a male actor.

For a female actor, you would usually say:

• la actriz

So:

• Con el papel protagonista, la actriz puede sobreactuar.

If you are talking generically about actors in general, context matters, but in this sentence el actor is most naturally understood as one specific male actor.

Here puede expresses possibility or tendency, not permission.

So el actor puede sobreactuar means:

• the actor may overact
• the actor can overact

It does not mean someone is giving him permission to overact.

If you wanted a more hypothetical or softer idea in Spanish, you might use:

• podría sobreactuar = he could overact

So puede here is a fairly direct statement about what is possible.

Yes, sobreactuar is one word.

It is built from:

• sobre- = over-, excessively
• actuar = to act

So it literally means to overact.

This is a useful pattern to notice in Spanish: prefixes are often attached directly to the verb or noun.

Related noun:

• sobreactuación = overacting

It is a normal and understandable word, especially when talking about theatre, film, or performance.

That said, in very everyday conversation, some people might also use longer alternatives such as:

• actuar de forma exagerada
• actuar exageradamente

Those mean roughly the same thing.

So sobreactuar is perfectly good Spanish, especially in artistic or critical contexts.