The former president of the European Parliament was officially introduced to the party in Willy Brandt House in Berlin this afternoon.
He comes from an SPD family in North Rhine Westfalia, close to the Belgian border.
The 61-year-old succeeds Sigmar Garbriel as leader of the SPD. Gabriel had little chance of defeating Merkel. The Rhinelander might well give Merkel a run for her money. If there is a reaction to the Trump administration then the SPD under Schulz could make large electoral gains.
The SPD is the oldest political party in Germany.
As from the weekend Sigmar Gabriel is German foreign minister. He replaces Frank-Walter Steinmeier, who is due to be elected German president by the Federal Convention on February 12.