После разговора с начальницей ему было не до шуток.

It is an idiomatic expression.

• не до X means not in a situation/state for X, not the time for X, or not up to X
• шутки = jokes

So ему было не до шуток means something like:

• he was in no mood for jokes
• it was no laughing matter for him
• he didn’t feel like joking

Literally, it is closer to it was not up to jokes for him, but that is not natural English.

Because после always takes the genitive.

• после = after
• dictionary form: разговор
• genitive singular: разговора

So:

• после разговора = after the conversation

This is a very common pattern:

• после урока = after the lesson
• после работы = after work
• после встречи = after the meeting

Because the preposition с in the meaning with usually requires the instrumental case.

• dictionary form: начальница = female boss / female superior
• instrumental singular: начальницей

So:

• разговор с начальницей = a conversation with the female boss

Compare:

• с другом = with a friend
• с сестрой = with a sister
• с учителем = with a teacher

Here с начальницей belongs with разговора:
после разговора с начальницей = after the conversation with the boss

Because Russian often uses an impersonal construction here.

Instead of saying:

• He was not in the mood for jokes

Russian says something more like:

• To him, it was not for jokes

That is why you get:

• ему = to him (dative)

This kind of pattern is very common in Russian when talking about physical or emotional states:

• мне холодно = I am cold
• ему плохо = he feels bad
• ей грустно = she is sad
• нам было весело = we were having fun

So ему было не до шуток is a normal Russian way to express his state.

This is another result of the sentence being impersonal.

There is no normal subject like он doing the grammar work here. The core is:

• ему было не до шуток

In this kind of construction, Russian uses было in the neuter singular past, which is the standard form for many impersonal past-tense expressions.

Compare:

• мне было трудно = it was hard for me
• ей было скучно = she was bored
• ему было страшно = he was scared

So было does not agree with ему. It is just the normal past-tense form in this impersonal structure.

Because the expression is не до + genitive.

So after не до, the noun goes into the genitive case.

• dictionary form: шутка
• genitive plural: шуток

Therefore:

• не до шуток = not in the mood for jokes / no time for jokes

You can see the same pattern in other expressions:

• мне сейчас не до сна = I’m not in the mood to sleep / now is not the time for sleep
• ему было не до разговоров = he was in no mood for conversations
• нам не до смеха = we’re not in the mood for laughing

Yes. Начальница specifically means a female boss/superior.

• начальник = boss, superior, chief
• начальница = female boss

It is completely normal Russian. In English, people often just say boss regardless of gender, but Russian can mark the gender more explicitly.

Depending on context, English might translate it as:

• his boss
• the boss
• his female boss

Even though Russian uses the feminine noun, English often does not need to emphasize that unless it matters.

Because Russian often leaves possession unstated when it is clear from context.

In English, you often need to say:

• after talking to his boss

In Russian, if it is obvious whose boss is meant, you can simply say:

• с начальницей

The listener normally understands it from context.

If you wanted to make it explicit, you could say:

• с его начальницей = with his boss

But very often Russian avoids possessives when they are unnecessary.

Yes. Russian word order is flexible, although different orders can change emphasis.

The neutral order here is:

• После разговора с начальницей ему было не до шуток.

Possible alternatives include:

• Ему после разговора с начальницей было не до шуток.
• Не до шуток ему было после разговора с начальницей.

These all mean roughly the same thing, but the emphasis shifts:

• starting with После разговора... highlights when/after what
• starting with Ему... highlights him
• starting with Не до шуток... highlights his mood/state

For a learner, the original version is a very natural, standard order.

Here разговор simply means conversation or talk.

• разговор = a conversation, talk
• беседа = conversation/discussion, often a bit more formal, calm, or deliberate
• разговорить is not the same kind of word; it is a verb root meaning something like to get someone talking

In this sentence, разговор с начальницей could be anything from an ordinary talk to a serious reprimand. The phrase не до шуток strongly suggests it was unpleasant, tense, or serious.

So the mood of the sentence tells you more than разговор itself does.

Yes, very strongly.

The grammar itself does not explicitly say the conversation was bad, but the phrase ему было не до шуток strongly implies that afterward he felt:

• upset
• worried
• intimidated
• embarrassed
• tense

So a native speaker will usually understand that the talk with the boss was serious or unpleasant.

If the conversation had gone well, this ending would sound strange.

Not really. That changes the meaning.

• he wasn’t joking = he was serious, he meant what he said
• ему было не до шуток = he was not in the mood for joking / joking was the last thing on his mind

The Russian sentence is about his emotional state, not about whether a particular statement was a joke.

Better translations are:

• After the conversation with his boss, he was in no mood for jokes.
• After talking to his boss, he didn’t feel like joking.
• After the conversation with the boss, it was no laughing matter for him.