Swede Isak, 25, is the first key player Newcastle have sold since Howe took charge of the club nearly four years ago.
Newcastle turned down an initial £110m bid from Liverpool last month. But after completing a club record move for forward Nick Woltemade, and lining up a deal for Yoane Wissa, they accepted an improved offer in the final stages of the window.
Howe said he hopes Newcastle can keep their prized assets moving forward.
“That’s what we want to do. We want to create an environment and home for them that they love being at,” he said.
“But I would say Alex was very much part of that and loved his time here so I don’t think that was the issue. I think the issue for him was more when the other club came [in], that then changed his thought process. I never had a day where Alex didn’t look like he enjoyed being here when he was 100%.”
Newcastle navigated the opening weeks of the season without a senior striker and options will still be a little thin on the ground for the Premier League visit of Wolves on Saturday (15:00 BST).
Wissa will miss the game at St James’ Park with a knee issue, joining suspended forward Anthony Gordon and injured midfielder Jacob Ramsey on the absentee list.
However, Woltemade is primed to make his debut after completing his £69m move from Stuttgart last month.
Newcastle initially experienced a number of knockbacks in their search for a striker as targets Hugo Ekitike, Benjamin Sesko and Joao Pedro all moved elsewhere. As a result, the club were keen to recruit players like Woltemade and Wissa who were “desperate” to join.
“It’s absolutely crucial,” Howe said. “It’s very difficult to work with players that don’t want to be at any football club. For me, it’s one of the most important things you look for in a player, especially when recruiting players.
“You can look at the ability and the person but if they are unsure whether to come and whether this is the right club for them, that leaves the transfer a very difficult one to complete.”
Some of Newcastle’s best signings have fitted that description.
Bruno Guimaraes, Dan Burn and Kieran Trippier, for instance, were prepared to join a club in deep relegation trouble in 2022.
“All the successful transfers we have had since I have been here have been undoubted in their desire and want to sign for the football club for many different reasons,” Howe added. “That could be multi-functional, but you can see that want and drive for them to be here and then that helps in their performance.
“In any difficult moments that they face, their love for the club and environment shines through.”
