Working on behalf of main contractor Bowmer & Kirkland, Hambleton Steel will erect approximately 1,000t of structural steelwork for the project.
City Hall will house not just Sunderland City Council offices but also public sector partners including housing provider Gentoo and the Department for Work and Pensions.
Designed by architect FaulknerBrowns, the building will be an impressive addition to the city centre and consists of two structures joined by a central atrium and rooftop pavilion.
Council Leader Graeme Miller said: “City Hall is a real game changer for the regeneration of Sunderland city centre and I’m delighted to see it going ahead.
“Its development is an essential element of our transformation plans to create a dynamic, healthy and vibrant city centre and deliver the step change that we know our residents want to see.”