The 44-year-old Anna Kinberg Batra was unanimously elected head of the Moderate Party during a party convention today.
Reinfeldt quit as prime minister in September after national elections, saying he would also let the party reins go.
During two terms, the 49-year-old Reinfeldt headed a centre-right coalition, which made tax cuts and pro-market policies that critics say have eroded Sweden's welfare system.
The government was replaced by the current left-leaning, minority coalition of Social Democratic Prime Minister Stefan Lofven.