President of the United States
The office of President of the United States has been held, or contested, by Columbians several times in the past.
Barack Obama is the only Columbia graduate to have actually held the office. Some others who later became president were drop outs, though, including both Roosevelts.
Other Columbia affiliates have held the office as well. For example, Dwight Eisenhower was University President immediately before assuming the presidency of the US. We're sure this is the experience that helped him clinch the deal.
Even George Washington has Columbia ties - his stepson attended King's College and he fought a Revolutionary War battle on what is now campus!