Erica had suffered major brain damage from a massive heart attack on Christmas Eve.
Her mother, Esaw Snipes-Garner, said her daughter went into cardiac arrest during an asthma attack and had since been in a coma.
Snipes-Garner says her daughter suffered her first heart attack not long after giving birth to a baby boy in August. Doctors said the pregnancy had put a strain on her heart, which was later found to be enlarged.
In 2014, her father, Eric Garner, who was black, was stopped on Staten Island for selling untaxed cigarettes and died after a white police officer subdued him with a chokehold. A grand jury declined to indict the officer; the city agreed to pay a $6 million civil settlement.
Garner's last words, "I can't breathe," became a slogan for activists.
Erica Garner became a voice for police accountability after his death, criticizing Democratic Mayor Bill de Blasio over policing matters. In 2016, she campaigned on behalf of Vermont Senator Bernie Sanders, an independent, for president.
The Rev. Al Sharpton, in announcing Garner's death Saturday, says she fought for justice and was "a warrior to the end."
Sharpton discussed the death of Erica Garner:
Garner's official Twitter account, run by her family and friends since she became ill, asked that she be remembered as a mother, daughter, sister and aunt with a heart "bigger than the world."
(Some information from the Associated Press.)