Learn Hardcore Korean: jibe gago naseo jeonyeogeul meogeoyo.

-고 나서 is a sequential connective meaning “after doing X (and only then) Y.” It emphasizes that the first action (going home) is completed before the second (eating dinner) begins.
By contrast, -고 alone can simply link verbs (“do X and do Y”) without stressing completion, and -아서/어서 often implies a direct result or a closer causal link (“so/then”), rather than a clear-cut, step-by-step sequence.

Why is 집에 marked with -에 instead of -에서?

With movement verbs like 가다 (“to go”), -에 marks the destination (“to the house”). -에서 marks the place where an action occurs (“at the house”). Since you’re going toward your home, you use 집에.

Why do we explicitly mark 저녁을 with the object particle -을, and is it possible to drop it?

The particle -을 shows that 저녁 (“dinner”) is the direct object of 먹어요 (“eat”). In spoken Korean, you can omit objects if they’re obvious, so 집에 가고 나서 먹어요 is grammatically fine and would still mean “after going home, I eat.” Including 저녁을 simply clarifies what you’re eating.

Why is there no subject in this sentence?

Korean often omits subjects when they’re clear from context (pro-drop). Here the speaker (“I” or “we”) and the time frame are understood, so no explicit subject is needed.

What politeness level is 먹어요, and what other endings could I use?

먹어요 is the polite informal style (해요체).
– More formal: 먹습니다 (합니다체)
– Casual: 먹어 (banmal/casual)
– Narrative/plain: 먹는다 (used in written narration or notes)

What tense and aspect does this sentence express? Is it a habit, a plan, or an ongoing action?

This is simple present tense (현재 시제) in polite form. In Korean, the simple present can describe habitual actions (e.g., “I usually do this”) or planned/near-future actions (e.g., “I will do this soon”). There’s no progressive aspect here; if you wanted “I’m eating,” you’d use 먹고 있어요.

Can I switch the order, for example say 저녁을 먹고 집에 가요, and what would that mean?

Yes—Korean clause order is flexible within limits. 저녁을 먹고 집에 가요 means “I eat dinner and then go home.” You’ve simply reversed the sequence so that dinner comes first. Make sure the verb you want to emphasize stays at the end.

What’s the difference in nuance between -고 나서 and -자마자?

-자마자 means “as soon as” with no delay between actions. It conveys immediacy (“I did X, and right away Y happened”). -고 나서 is more neutral, indicating “after X, then Y,” with no special emphasis on how quickly Y follows.