Rodney Lunn joined the Port in 2009 after spending 40 years working in the maritime sector.
His successor, Tom Willis, has already joined the Port after starting his handover in November.
Mr Lunn said: “I have been extremely proud to be chief executive of Shoreham Port over the past decade and it has been fantastic to work with such a dedicated and enthusiastic team.
“We have achieved a huge amount together to improve the Port’s facilities and as a place to work.
“I am very conscious of the role that the Port plays as an economic driver and I firmly believe that Tom’s superb leadership skills and strong track record of leading a diverse workforce will ensure the Port continues to maintain, manage and develop the Port for all of its stakeholders and customers.”
Under Mr Lunn’s leadership, the port has seen a 75 per cent growth in revenue from £8 million to £14 million, a port spokesman said.
The Port has also seen significant improvements every year with a focussed diversification of business across all streams.
During his tenure, Mr Lunn has made significant strides in strengthening the relationship between the Port and its surrounding communities, improving stakeholder engagement in accordance their Trust Port values, according to the spokesman.
The Port has also continued to provide jobs for many of those living locally, with the workforce doubling in size under his leadership.
Mr Lunn has ensured staff feel both valued and supported by making the Port a Living Wage Employer and by promoting gender equality in the workplace under the Women in Maritime Taskforce.
Amber Foster, chairman of Shoreham Port, said: “Rodney has shown excellent leadership over the past 10 years and he will be greatly missed.
“His contribution to Shoreham Port, the local community and Port sector has been enormous, and his legacy will no doubt be felt for many years to come.
“Rodney’s mantra has been that while Shoreham Port may not be the biggest, it can strive to be the best.
“This has meant hiring the best staff and training everyone to deliver a first-class service to customers and stakeholders.
“Thank you from everyone on the Board and very best wishes for the future, Rodney.”