Ms Surgeon, who was most recently based in Northern Trust's Melbourne office, will also retain responsibilities as head of client services for Australasia.
Her new role, which will be effective on 1 June 2017, will include responsibility for industry, client and consultant relationships in Sydney.
Ms Surgeon will continue to report directly to Northern Trust head of Australasia Madeleine Senior.
"We continue to see an increasing demand for our range of innovative institutional-level asset servicing and asset management solutions across Australasia," Ms Senior said.
"Sally has been instrumental in growing our client base across the region and we are delighted to appoint her to lead our Sydney office where, drawing on her experience, she will focus on continuing to deepen relationships with our clients and the industry and drive momentum for our expanding business," Ms Senior said.
Ms Surgeon, who has 20 years of experience in financial services, joined Northern Trust in 2005, in London, before moving to Northern Trust’s Melbourne office in 2007.
