Abraham Lincoln helped put Union Pacific in Omaha.Because of that much more people were passing through the city. Without him the city wouldn't have had nearly as many people or jobs.
Edward Creighton founded Creighton University. With that he helped better education in the city, If not for this person, less people would be coming into the city for an education.
Logan Fontnelle helped negotiations in relations between the U.S. government and the Omaha Tribe. Without him a light wouldn't have shined as bright on the city. If not for him, we could be over run by native americans and never grow as an economy.
Thomas Cuming served as the first Secretary of the Territory of Nebraska. He made preparations for the first legislative session. Without Omaha, all we would be known for this the guy who drank water and died
I almost chose Francis Burt because he drank some water from the Missouri River and died, and I think that's pretty funny.