Species are only considered invasive if they become widely established in sustaining, wild populations. If the species is widely cultivated, but rarely or never escapes cultivation, it is not invasive. Even if it widely escapes cultivation, it may not necessarily be invasive because it might not be vigorous enough in the wild.
Corn has escaped and formed wild sustaining populations in North America, including in the Midwest. Here is BONAP's range map:
It shows that it is established in all lower 48 states as well as many of the Canadian provinces that border the US. However, if you look at the county-level distribution, you will see that it is spotty.
Given how widely it is cultivated in many of those states (it covers much of Iowa and Illinois, for instance) yet how sparsely it is established there (it only shows up as established in the wild in isolated counties in both states, this provides pretty strong evidence that it's not really that vigorous in the wild.
I have also observed corn plants growing in the wild in the US. They aren't particularly vigorous: there will be one plant here or there, and it never dominates or forms large monocultures. Those highlighted counties are where corn has formed some sustaining population. Not necessarily where it is vigorous, common, or abundant.
Want to see what a map of an invasive species looks like? Here is BONAP's map on garlic mustard, Alliaria petiolata, widely agreed to be invasive:
In spite of the fact that it is not cultivated, it is found in nearly all counties of broad regions from Wisconsin/Illinois east through New England. Furthermore, if you examine it in the wild, you find it forming huge monocultures, shutting out all sorts of other plants.
But back to corn:
The ecological damage caused by corn in North America is not caused by wild corn, i.e. not caused by corn as an invasive species. Rather, it is caused by the agriculture itself, specifically, by vast monocultures of corn and other crops, and various other aspects (fertilizer and other chemical applications) of yield-intensive agriculture.
So I think the answer here, even accounting for the high level of subjectivity in the definitions of "invasive", is definitively no.