Nicknamed Alex, Hagan was born on 21 March 1991 in Bunbury, Western Australia. She grew up in the Perth area, where she attended Kearnan College Manjimup and Street Joseph"s Primary School, Bunbury before going to high school at Bunbury Catholic College.
She was selected to represent Australia at the 2012 Summer Olympics in rowing. As of 2012, she lives in Bunbury, Western Australia. Hagan is 179 centimetres (70 in) tall and weighs 76 kilograms (168 lb).
Hagan is a rower competing in single scull, double sculls and eights races.
At the 2008 Australian Championships, she placed first in the under-19 women's single scull event. She repeated this victory in the same category at the 2009 Australian Championships.
In 2009, she and Maddie Edmunds also finished first in the under-19 women's double scull event. In 2009, she competed at the World Junior Championships in Brive la Gaillarde, France, in the quad boat, finishing second in the 2000 metres race.
Hagan finished 5th in the eight event at the 2012 World Cup 3 in Munich, Germany and 4th in the same event at the 2012 World Cup 2 in Lucerne, Switzerland.
She was selected to represent Australia at the 2012 Summer Olympics in rowing in the eights. Rowers in the eight boat have nicknamed their team the "Motley Crew". Hagan will be one of the youngest amongst Australia"s of forty-six member rowing team
Prior to going to London, she participated in a training camp at the Australian Institute of Sport European Training Centre in Varese, Italy.
As a member of the eights crew in the 2000m course, she helped set a time of 6 minutes 12.36 seconds which qualified her and the rest of the team for the Olympics.
