The announcement from Avanti West Coast completes a full U-turn on its decision to scrap the service as part of a reduced timetable.
The issue has sparked major concern from local politicians, who had criticised the rail company for taking the decision without consulting.
Avanti said the latest announcement would come with the caveat that weekend engineering work could affect services in future, while this Saturday's RMT strike will also see no trains operating in the entire county.
Avanti had included the cancellation of the route as part of a revised timetable it said was needed due to staff shortages caused by sickness, industrial action, and the majority of its drivers making themselves unavailable for overtime.
The service departs Shrewsbury at 6.39am, and returns to the county from London Euston at 6.23pm.
Although the full resumption of the service seven days a week has been welcomed, it has still not been restored to its pre-pandemic status.
Prior to March 2020 there were two direct trains to the capital every day.
One was cancelled as a result of the pandemic and is yet to be restored.
Telford & Wrekin Council leader, Councillor Shaun Davies, had described the move to drop the service last week as unacceptable.
He said: "Avanti clearly made the wrong decision to suspend this service last week, putting additional pressure on Transport for Wales (TFW) and West Midlands Trains (WMT). I made my position very clear, as did others, that this was totally unacceptable and a massive blow to Telford and Shropshire.
“Whilst I am very pleased that Avanti have clearly listened to our concerns and have reinstated the service, I’m disappointed they made a poor decision in the first place without notice or indeed consultation. If this had not been challenged our residents would have been left with no direct service to London."