Nicole "Nicky" Reagan-Boyle is the only child of Erin Reagan and Jack Boyle. Nicky is a generally well-behaved and intelligent girl who dresses and typically behaves with more maturity than her classmates. She is being raised by her mother Erin because her father did not want to share custody.
As of season 6, Nicky is attending Columbia University, her mother's alma mater.
The oldest of the Reagan grandchildren, like her mother she is the only female grandchild. Overall, Nicky is a well behaved young woman, although there have been times where following her heart has led to her clashing with authority. While she resented being treated like a child longer than many of her classmates she also showed understanding that, as a Reagan, expectations of her were different.
Typical of the Reagan family, she attended Catholic schools, most notably Blessed Heart Academy for High School. She had considered college out of state heavily until she began to consider the cost and distance. Eventually she decided on Columbia, in part due to a friend having an apartment just off campus that she could share to save money.
In her early teens, Nicky announced that she wanted to be the first female Reagan cop. From time to time she wavered on her conviction to join the family business, classifying herself as the bleeding heart hippie of the family but has proceeded to go ahead and take the police exam.