Southgate said: "I am very grateful for the backing the chairman has given me this summer.
"I knew fairly much throughout who I wanted and we managed to pick off most of the targets we went for.
"You are never going to complete every deal, you are never going to be able to get everybody you look to sign, but I am delighted with the additions we have made.
"You need people to come in and have an immediate impact, which is important.
"But all of those players are of an age where they could be with the club for any number of years, and I think we have assets now.
"In investment terms, a couple of years ago, we were never able to sell a player; this year, we have been able to sell two and bring £13million in.
"We have shown a willingness to balance the books with the players we have moved on, and we have invested soundly, not just for now, but we have got players at the sort of age that they can be a big part of this club for the next three or four years, and that's very important."
Southgate also said: "The fans recognise what we have bought and they can see the change of style we are trying to implement.
"They realise those things take time and that we have brought in players around the age of 24, 25 - we have dramatically lowered the average age of the squad over the last 12 months.
"But I am really pleased with what we have done. The types of character we have brought in are as important as anything to me.
"There is loads of quality out there in terms of talent, but character and leadership are very, very important, and we have brought several players to the club this year who bring those qualities."