Hitler wasn't elected. He lost the Presidential election in 1932.

Hitler then had to change plans. The NSDAP (Nazi Party) never gained a majority of seats in the Reichstag. This meant that they were not able to, at first, to govern on their own. This fact lead the president of Germany, Hindenburg (who defeated Hitler in the 1932 election), dissolving the German Parliament on a number of occasions as the parliament was seen to not be working as no party, or coalition of parties was able to form a government to be able to run the country. There were a number of elections (not presidential elections but parliamentary) to try and break this deadlock.

The NSDAP ended up as the single largest party (held the most number of seats in the Parliament) but Hindenburg hated Hitler and did not want to appoint Hitler as the Reichskanzler (Chancellor). The problem with this was that as the largest party, and the other parties not being able to work together, this meant that the Nazis could effectively choose what got blocked and what didn't. Eventually the Reichskanzler approached Hindenburg and asked Hindenburg to appoint Hitler as the new Reichskanzler in the hope that would at least lead to some stability.

However, as the president Hindenburg was technically Hitler's boss and could have fired him. When he died in August of 1934 Hitler illegally took Hindenburg's position of Reichspraesident and combined it with his own position of Reichskanzler and named the combined position as Fuehrer und Reichskanzler. At this point Hitler became the dictator of Germany without technically winning an election.