"It's great that a child of Soweto can stand up here and be your leader today," Maimane, who is also the Democratic Alliance's spokesperson, told the hall of delegates at the Democratic Alliance's elective congress in Boksburg on Sunday in Boksburg on Sunday.
The pair, along with incumbent Anchen Dreyer, was elected from nine candidates to the three deputy federal chair positions.
Delegates leapt to their feet and cheered as Maimane and Gana's names were announced as leaders.
"Amandla! Phambili DA! Phambili!," Maimane said as he took to the stage.
"We are the future of the DA," Gana, the DA's federal youth chair, said.
"We will work together to make sure South Africa is governed by responsible people."
The duo replaced fiery DA police spokesperson Dianne Kohler-Barnard and Western Cape minister of social development Ivan Meyer.
Wilmot James was re-elected DA federal chairperson, beating out controversial DA MP Masizole Mnqasela to the position.
Leader Helen Zille retained her position uncontested.
She said the DA's main objective would be to govern in provinces and cities around the country – with a special reference to South Africa's economic hub Gauteng.
"It is possible for us to become government in more places than possible ever before. It is really possible to make Gauteng blue," ZIlle told delegates.
Zille also said the DA was now the only party who supported and defended the Constitution.
"[The ANC] used to be a party of constitutionalism [and] non racialism but this no longer true. The ruling party will eventually disintegrate."