Southend Borough councillors voted 15 to one in favour of the store at the former B&Q site next to Southend Victoria train station.
An earlier application was deferred by the council in August over concerns about potential traffic congestion, leading to a change in road designs.
The four-storey scheme is expected to create up to 450 jobs.
The development also includes plans for a footbridge from the store to the Victoria shopping centre.
The existing Focus Youth Centre, which is currently on the land, will also be rebuilt.
Bill Harkness, managing director of Delamere Estates, which owns the Victoria shopping centre in Southend, said he believed the development would bring an “infusion of blood” to the centre.
He said: “I think it will also encourage a lot of people we’re talking to about taking up the vacant units in the centre, to re-look at the scheme and be encouraged to come into Southend.”