Police and a Korean interpreter negotiated with Seo, 38, for more than 12 hours.
The police operation took place in front of hundreds of Chatswood office workers, including some in surrounding high-rise buildings overlooking the balcony roof.
At a number of points throughout the stand-off he hung his leg or his head over the edge, often looking down on the crime scene tent erected to conceal the body in the alley below.
Brown Street remained closed to all vehicles and pedestrians throughout the day, while police had to leave the body under the crime scene tent due to safety concerns until Seo had been brought down off the building.
Police successfully removed him from the rooftop shortly after 7pm.
After attending Royal North Shore Hospital as a precaution, Seo was taken to Chatswood police station where he was charged with assault occasioning actual bodily harm relating to an earlier incident.
However, that charge was upgraded to include murder when his matter was heard at Hornsby Local Court on October 20.
In the NSW Supreme Court on Friday, Seo – through a Korean interpreter – pleaded guilty to murdering Ms Choi.
Seo is scheduled to face a sentencing hearing on March 1, 2019.
From 2014 until the start of 2017, Ms Choi was an employee of ANZ bank, latterly working as a business bank manager, and before that as a home and investment lending manager.
In the days following her death, tributes were left, including flowers and a handwritten note with the message: “I don’t think I looked after you as much as I could have.”
National domestic violence helpline: 1800 737 732.