Brad Nagel, an Iowa local, is a "Senior Political Advisor" for Trump's presidential exploratory committee in Iowa.

I have a feeling Trump hired him because of the memes. (via The Daily Beast)

Nagel was most likely hired since Iowa is a swing state and Trump needs as much support and expertise as he can get in there. The Daily Beast did a bit of investigative work into Nagel's past and found a bunch of racist memes he posted from the 2012 election. Now, I'm not usually in support of publicly shaming someone for some old posts they did, since these instances of public shaming often don't factor in circumstance or context. But the memes Nagel posted are pretty damn egregious for a grown man working for a presidential candidate whose campaign run is going from a punchline to a reality. They're part of that far-right, hate-mongering, conspiracy-theory mode of thinking, and also just plain inaccurate. First off, there are the Obama Hitler comparisons:

Sources: The Daily Beast