Bednarek finished with a personal best of 19.68, just behind Canada's Andre De Grasse, who set a national record at 19.62 seconds.
Another American, Noah Lyles, took home bronze.
Bednarek finished second in his 200-meter semifinal heat Tuesday evening in Tokyo with a time of 19.83 to qualify for Wednesday's final.
He was born in Tulsa, Okla. and then moved to Rice Lake, Wis. before attending Indian Hills CC.
Bednarek wins silver in men's 200-meter final
You can find a full list of Olympic athletes with Iowa ties here.
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