Lee Johnson added nine first-team players to his squad during the window
Corry Evans, Alex Pritchard, Callum Doyle, Dennis Cirkin, Frederik Alves, Nathan Broadhead and Niall Huggins have all arrived at the Stadium of Light.
And they were joined by Ron-Thorben Hoffmann and Leon Dajaku on deadline day.
But what happened to the deals that Sunderland weren’t able to get over the line and where did those players end up?
Here, we take a look:
1. Josh Key
Sunderland were said to have offered a six-figure fee for the right-back but Exeter rejected it and the player remains at St James' Park. Photo: Harry Trump
2. Jordan Jones
Sunderland were linked with a move for their former loanee very early on in the window. However, Jordan Jones opted to sign for Wigan Athletic alongside former Black Cats Charlie Wyke and Max Power. Photo: Bryn Lennon
3. Daniel Jebbison
The Sheffield United striker was heavily linked with a move to Sunderland and was even in attendance at the Stadium of Light for the pre-season clash against Hull City. But the attacker ended up joining League One rivals Burton Albion on loan. Photo: George Wood
4. Djibril Cisse
Now this one was definitely tenuous. The 40-year-old former striker issued a come and get me plea to Sunderland on social media but the move was never actually on the cards. Photo: Bryn Lennon