in 2019, I am spending 5 days in Albania (a nonSchengen country) and then flying into Rome, Italy for 5 days before going to the United States. I am a US Citizen. Do I clear customs in Rome after my visit to Albania?
Yes, not only customs, but also immigration checks.
Entering Italy from a non Schengen country, you are subject to immigration checks (passport control). Entering Italy from a non-EU country, you are subject to customs checks.
It is for your question irrelevant that you are a US citizen or that you are staying 5 days.