Skanska will deliver building services and fit-out for 866 prime residential apartments, located in two buildings just west of the power station.
Carillion won the £350m first phase known as Circus West, fending off bids from Laing O’Rourke and Brookfield last year.
Work on the £90m fit-out contract is set to commence in September and scheduled to conclude in October 2016.
Martin Neeson, managing director, said: “This contract is great news, not just for Skanska, but also for our client and eventually for those people who will be living in the newly-built homes.
“Residential schemes are a strategic priority for our engineering business and this development offers an opportunity to build on our successful work at One Tower Bridge.”