Его уволили вчера.

Because его is the object form, while он is the subject form.

• он = he
• его = him / his

In Его уволили вчера, the man is receiving the action, not doing it, so Russian uses его.

Compare:

• Он уволился вчера = He quit yesterday
• Его уволили вчера = They fired him yesterday / He was fired yesterday

Here it means him.

Его can mean either him or his, depending on how it is used:

• Я вижу его. = I see him.
• Это его машина. = This is his car.

In your sentence, его stands alone after a verb, so it is the direct object: him.

It is in the accusative case.

The verb уволить takes a direct object, and direct objects usually go in the accusative. Since the object is a person, the pronoun appears as его.

A useful point: for this pronoun, the accusative and genitive forms look the same: его.

Because Russian often uses a 3rd person plural verb with no stated subject to mean they, someone, or people in general.

So уволили literally means they fired, but it does not have to refer to a specific group. This is a very common Russian way to avoid naming the subject.

So the sentence is literally:

• They fired him yesterday

But in natural English, we often translate it as:

• He was fired yesterday

Grammatically, it is active, not passive.

The structure is:

• его = object
• уволили = they fired

But because the subject is omitted and vague, English often translates it with a passive:

• He was fired yesterday

A more direct Russian passive version would be:

• Он был уволен вчера

That version is correct too, but it is more formal and less conversational than Его уволили вчера.

Уволили is:

• past tense
• plural
• perfective aspect

It comes from уволить.

Why perfective? Because it describes a completed event: the firing happened and is finished.

If you used the imperfective увольняли, the meaning would change. It could suggest process, repetition, or background context rather than one completed event.

Because Russian is not using a passive structure here.

English says:

• He was fired

But Russian often prefers:

• Его уволили
• literally: They fired him

So there is no need for был in this sentence.

If you want a true passive with was, then Russian can say:

• Он был уволен вчера

Yes. Both are natural.

Russian word order is flexible, and changing it usually changes emphasis, not the basic meaning.

• Его уволили вчера — slightly highlights yesterday
• Его вчера уволили — may sound a bit more neutral, or put a little more focus on fired

In real speech, intonation matters a lot too.

Уволить means to dismiss someone from a job, to fire someone, or to let someone go.

It is a general employment word. Depending on context, it may or may not imply bad behavior.

So it can correspond to English words like:

• fire
• dismiss
• let go

The exact nuance comes from context.

It is usually pronounced roughly yeVO.

A useful special point: in this word, the written г is pronounced like v.

So:

• его → roughly yeVO

This is normal for его and some related words.

You would use её instead of его:

• Её уволили вчера. = She was fired yesterday

The verb уволили would stay the same, because the hidden subject is still the indefinite they. Only the object pronoun changes.