The Verdict: Not eligible
One great-grandparent, or ancestry further back, is not enough for the Polish origin test. Look at our ancestry route instead, which has no generational limit.
A person of Polish origin needs at least one parent or grandparent, or two great-grandparents, of Polish nationality. Nothing further back counts.
Count the whole family before concluding. The two great-grandparents need not be a couple or on the same side, so all eight are candidates, and people often stop at the one they knew about.
Descent is a different test: Polish citizenship passes with no generational limit, so an ancestor five generations back who was a Polish citizen and never lost it can still found a claim.