Speaking at the Equality Forum at the University of the Arts, Philadelphia, Castro said that she was ‘very proud' of the work done to promote LGBT equality in Cuba, of which she played a leading part, reported The Philadelphia Inquirer.
‘We can make the best together,' she said to a round of applause.
Castro, a sexologist and director of the Cuban National Center for Sex Education (CENESEX), has long been an activist for LGBT equality in Cuba.
She led several successful campaigns over the last decade to promote acceptance of LGBT Cubans and policies to help tackle HIV/AIDS infection on the island.
Castro launched free condoms distribution and safer sex literature that led to Cuba having one of the world's lowest HIV infection rates.
HIV positive Cubans also have access to free anti-retroviral treatment.
Castro was also instrumental in the decision of the Cuban government to offer free gender-reassignment surgery in 2010.
Malcolm Lazin, the Equality Forum's executive director, stated that Castro had made ‘real changes' to reduce oppression of gay men and women in Cuba.
Castro was initially denied a US visa to attend the event, but the State Department eventually reversed its decision, allowing her to arrive in Philadelphia on Friday where she visited the Liberty Bell.
Republican Congresswoman Ileana Ros-Lehtinen of Florida slammed the Obama administration's decision to allow her entry as ‘obtuse'.
She said that it was ‘shameful, pathetic and a ruse' to give her an award because ‘human rights don't exist in the vocabulary of the Castro tyranny.'
Castro was reported to defend her country, saying: ‘There is not any government or any country who has the right to impose or make decisions to the other ones regarding the human-rights area.'