Polanco was born in the Dominican Republic and moved to the United States at a young age. She was raised in Brooklyn and Miami by her father Rubén Darío Polanco, a mechanic, and mother Janet Polanco, a cosmetologist.
Polanco aspired to be an actress from an early age but "always doubted auditioning because of [her] weight", and so she completed a bachelor's degree in psychology at Hunter College. After college she began working in the healthcare industry with the intention to become a nurse. She was working as a hospital administrator at Montefiore Medical Center in the Bronx whilst studying nursing, when her fiancé encouraged her to pursue acting again and paid for her registration with an acting studio as a gift. She attended BIH Studios in New York, which is where she was signed by the talent agency Shirley Grant Management. Her first acting credits were minor parts on the television series Unforgettable and NYC 22.
In 2012 Polanco was cast in the Netflix series Orange Is the New Black as Dayanara "Daya" Diaz, an inmate in a women's prison; it was her first full-time acting job. She subsequently appeared in the 2013 independent film Gimme Shelter before returning to her role on Orange Is the New Black for the show's second season. In June 2014, it was announced that she had been promoted from a recurring role to a series regular for the show's third season, which was released in 2015. She also appeared in the comedy film The Cobbler, which was released in September 2014. In her most recent work, she appeared as Jackie, the childhood best friend of Jennifer Lawrence, in the 2015 film Joy.
Polanco has two children, Dasany and Aryam, and is engaged.
She recently told Huffington post about her fiancé and having three children.Dascha revealed to The Huffington Post that she’s engaged to a “good-hearted man”. They met at the Dominican Day parade and he supports her. And while the actress has a “tricky” relationship with her family, she says she’s got her man and three kids to keep her company.
As of 2015 Dascha opened up about her personal struggle with depression and mental health after not only becoming a mother at the age of 18, but her mothers passing at age 46, leaving the then teenage mother alone to raise her daughter while juggling work and motherhood.
She shared her struggle saying "I remember having to find someone to care for my daughter because I did not want to stop school and couldn't stop working".
Despite her fame and new "Latino cover girl status" Polanco did not have an easy start in life and believes that everyone makes their own decisions and their own choices.
She states, "My parents taught me that God is going to send you obstacles in life and you have to overcome them", which she says put her at ease and helped her with the challenges she faced in real life prior to her success.