The 49-year-old will take over from current mayor Klaus Wowereit in December. Wowereit announced his resignation in August after his popularity nosedived with the city’s failed attempt to build a new airport.
Müller took 59.1 percent of the vote among the SPD’s Berlin members, beating Jan Stöß with 20.8 percent and Raed Saleh who secured 18.6 percent.
Just over 11,000 SPD members voted out of a possible 17,200.
Müller was born and raised in Berlin and had more name recognition and political experience than the two other candidates.
Like his father before him, the trained printer was active in the SPD from a young age. In the party since 1981, he was the head of the SPD in the Berlin parliament from 2001 to 2011.
Between 2004 and 2012, he was head of the SPD in Berlin. He is also in charge of Berlin senate’s biggest portfolio - urban development and environment.
The 49-year-old is close to Wowereit, but in contrast to the colourful outgoing mayor, Germany’s newspapers describe a pragmatic, dependable man with little charisma. Welt newspaper calls Müller “friendly, effective, but a little pale in public”.
The Tagesspiegel - despite also saying Müller was “objective to the point of boredom” - said Müller’s lack of vanity and desire for the spotlight should be counted as a strength.