that would be Busan

Great :)

This was the first part of your post:

"i'm from the US and taking a cruise from Hong Kong thru many other countries before entry to Shiaghai will my confirmed flight ticket back to US qualify for the 144 hrs. free transit visa? thank you"

Now, we know that your itinerary will be Busan - Shanghai - US

This is definitely eligible itinerary for 144 hour visa free transit in Shanghai area. There is just one more condition and that is, your flight to US is not allowed to have any additional landing within mainland China and in South Korea.

If this condition is fulfilled, you can enjoy your stay in Shanghai area absolutely visa free.