Danielle was born Danielle Marsh/Mo Ji-hye on April 11, 2005 in Newcastle, New South Wales, Australia. Her father is an Australian man named Andrew Marsh, and her mother is a South Korean native named Mo Ji-won (모지원).
She was a student at Munsan Elementary School. When she was three years old, Danielle moved with her family to South Korea, where they remained until 2012. In October 2019, Danielle returned to South Korea after passing BigHit's Australian Global Audition and became a trainee.
On July 21, 2022, NewJeans released a pre-debut music video featuring Danielle for their song "Attention". They officially debuted on August 1, 2022 with the EP New Jeans.