On Friday 21 February, Mr Christopher O'Neill met with the press at Presbyterian Weill Cornell Medical Center in New York.
Mr O'Neill explained that both mother and daughter are in good health, and said: "She looks like her mom. It was an incredible feeling to hold her."
The baby weighed 3.15 kg at birth, and was 50 cm long.
Mr O'Neill was present at the hospital throughout the birth.