Impact upon my future international travel due to my Canadian entry denial

I was told that I could return to the USA, but only after I signed a voluntary withdrawal of my application to enter Canada

So technically you were not denied entry into Canada, a voluntary withdrawal of application at the US/Canadian border between their citizens is not that big of a deal. This alone will not be a reason to deny you entry into other countries.

There is no need to state on future visa or visa free entry applications that you were once denied entry into Canada. And it is not lying either. Unless specifically asked about this incident, you don't even have to narrate it.

What happens when you’re denied entry to Canada

Whatever the reason for you being stopped at the Canada/US Border or Airport, there are a number of “scenarios” that could play out, each having differing implications.

The most common scenario we see is that a CBSA officer simply refuses you entry to Canada and “allows you withdraw your application for admission” This amounts to a legal “slap-on-the-wrist” . In such cases, officers will usually advise you to return to Canada with sufficient documentation and information that proves you are a genuine temporary resident i.e., visitor, student or worker. Documents showing your ties to your home country are generally what the CBSA officer is looking for.

.....

If you have a criminal record or if you may not be able to demonstrate your intentions to enter Canada as a temporary resident, make sure that you consult with an immigration lawyer before attempting the enter Canada to avoid being denied entry to Canada.

Source: Michael Niren

^{According to the linked source, Michael is a graduate of Osgoode Hall Law School in Toronto. He is a member of the Law Society of Upper Canada, the Canadian Bar Association’s Citizenship and Immigration Section and the Associate Member of the American Bar Association.}

However, the reason you were told to go back may well be Criminal Inadmissibility which itself may become a deciding factor in the future if your destination receives the data from the US.

Must Read: Denied Entry Into Canada