0345 GMT August 23, 2019
In her final annual report, Professor Dame Sally Davies said focusing on domestic issues could risk failing to control global threats such as Ebola, BBC wrote.
And she said learning from other countries would also ensure the UK National Health System (NHS) was not left behind.
After nine years as CMO, she is to become Master of Trinity College at the University of Cambridge.
Davies said: "Investing in global health is the smart thing to do because it is in our mutual interest. It creates a better world for us and for future generations.
"It helps to keep our population safe.
"We should invest in systems and solutions that contribute to making health more equitable, secure and sustainable.
"What we learn abroad will improve our NHS and support our domestic efforts to make sure no-one in the UK is left behind."
Davies cited last year's monkeypox outbreak in the UK — the first cases of the disease outside Africa since 2003.
She said UK collaboration with the Nigerian Center for Disease Control helped to contain and manage the situation, and minimize the public health impact.
And, as in the 2014 Sierra Leone outbreak of Ebola, UK experts are helping those dealing with the current outbreak in the Democratic Republic of Congo.
Another focus for global health initiatives should be the rise of non-communicable diseases including heart disease, strokes and cancer, said Davies.
They are set to be the leading causes of death across low-income countries by 2021.