Travel to Italy from US; layover in Amsterdam

As you will enter the Schengen Zone in Amsterdam, you'll go through passport control there, and another security check as well to catch your next flight. You'll go through customs in Venice but if it's like Rome, it's just a wak though the gate with the green "nothing to declare" light.

Are you checking luggage?

customs, passport control in Amsterdam. The airline agent I called seems to think that I would not be going through that in AMS, but in Venice.

People from outside Europe often mix up Immigration (passport control) and customs. They are two different things.

The Netherlands and Italy are both in the EU (a customs Union), and both in the Schengen Area (a passport Union).
There are no passport controls between the Netherlands and Italy.
You will go through passport control in Amsterdam. As a US citizen, your passport will be stamped in Amsterdam, and that is the start of your "90 days in any 180" in the Schengen Area.
Assuming this is one through ticket (big if), your luggage will be labelled through to Venice, you will not see it at Amsterdam. In Venice, your luggage will go through customs. It will have a different type of luggage label which is how customs can tell it came from outside the EU. However, this is a non-issue, you just walk through the "nothing to declare" exit, and only a random sample are stopped.

But BUT. One hour is very short for changing planes from an intercontinental flight and going through Immigration at Amsterdam. If you have this as a through booking, it is not your problem. If you miss the connection, it is the airline's responsibility to put you on the next flight.
If this is two bookings, panic now. You have been warned.

No, I am not checking in luggage.

This is a through booking, so they'd put me on the next flight available. But I'm hoping I don't miss it at all in the first place. I pre-booked a Venice train at night, which I should be able to make even if I miss my flight and the next flight afterwards (2-3 hours later).

Can someone give me the run-down process of doing the transfer in Amsterdam? I'm not provided with any gate numbers yet.
I'm flying from Detroit, MI to Amsterdam through Delta Airline. Then KLM from Amsterdam to Venice.

Is the arrival and departure gate in each other's proximity? Do I have to take a detour to go through passport control?

Another annoying part is I'm seated in Row 18 on my flight to AMS, in the middle. That was the furthest up I could get. So I'm definitely not going to be one of the first few people getting off the flight either.

when you arrive in Amsterdam just make your way to the departure gate for your connecting flight

you don't make a detour for immigration - it will happen on the way to the next gate

Amsterdam is an easy place to connect

Don't worry about this transfer - for several specific reasons.

1) You won't be allowed to miss any necessary steps. It's not like you can bypass immigration or customs or security, then get in trouble. These things aren't optional; if they're required, you won't be able to proceed without going through them.
2) Just follow the crowds. Many of the people getting off your plane will be going to the same places you are. Some, of course, will be going to other places, but it's not like you have to figure this out all by yourself. However, do make sure you don't follow someone who's going to another destination. For instance, someone connecting in Amsterdam to Morocco will not be going through passport control, whereas you need to.
3) Amsterdam is a well labeled airport. Remember that no one in the airport (airlines, security, etc) wants you getting lost or missing planes; it just makes more work for them! So, they really do try to make it straightforward.

If at any point you are lost or unsure, be sure to ask someone for help right away.

Have the flight number of your AMS to VCE flight handy. I find that, tired and jet lagged, I keep forgetting it, and since there can be multiple flights on multiple airlines, all going to the same place, you do need to make sure you go to the right gate for YOUR flight!

Thanks everyone.

Also, I just checked the flight arrival history of my flight to AMS. It appears to early by at least 30minutes.

My favorite route is DTW to AMS and connect from there, if I can't find a non-stop. Schipol airport is very straightforward. If your flight from DTW is on time, an hour is plenty of time.

Also at the immigration checkpoint there will be an express lane for those folks with flights departing very soon. There will be a monitor overhead of the lane showing which flights qualify at that moment.

Dzdang, you might find this thread discussion helpful:
https://community.ricksteves.com/travel-forum/netherlands/60-minute-layover-in-amsterdam-81b8f6e3-e29b-4153-9fdc-3689f1ff5a9a

I actually had the exact same concern as you and asked the same question over in the Amsterdam forum a while back!

In April, I'll be going from MSN-DTW-AMS-VCE, also with a 1-hour layover in AMS.

Have fun! :-)

Thanks all. Very insightful.

Make sure you get BOTH your boarding passes when you check in for your US - AMS flight. An hour or two before landing in AMS, tell the cabin crew that you have a short connection. Often they will be able to get your gate number before you land and they may even expedite your exit from the plane. When you get into the AMS airport ask officials immediately where to go. Don't be shy about showing your boarding pass and explaining to anyone that your next flight is boarding soon.

There will be a security check before you board the Venice flight. In most airports, the security check is just as you enter the airport, but in AMS it's often at the boarding gate.