Southwark's cabinet is expected to agree the purchase of the 128-bed care home overlooking the Bricklayers Arms junction at a meeting next week.
The care home - which largely looks after people living with dementia - has a chequered record with the Care Quality Commission.
In 2022 the council - which funds many of the home's residents - was ordered to compensate the family of a woman who had been accidentally locked in a cupboard.
Once the council has completed the freehold purchase of the building, it will seek a new operator for the home.
“This is really good news for residents, staff and, indeed, our borough," said Cllr Evelyn Akoto, Southwark Council's cabinet member for health and wellbeing.
"By stepping in, we are protecting much-needed nursing home beds and local jobs in our borough.
"Residents will stay close to family and friends, which is so important.
"We will continue to work closely with HC-One to ensure a smooth handover in due course.”
Residents and their families, as well as care home staff, have been informed of the plans.
Stephen Butterworth, chief operations officer at HC-One, said: “We believe that Tower Bridge Care Home will have a bright future under the tenure of Southwark Council who will enable the home to flourish.
"We are grateful for the council’s support to date, and we look forward to working with them over the coming months to support a successful transition, which will ensure the long-term care provision for the people of Southwark and employment for colleagues who work at the home."