"I think it's a fantastic situation," Tisdale told BBC Devon. "I can't believe anybody would not want Ryan with us for the rest of the season.
"Only one club was looking to spend money on him, and that club didn't offer a great deal of money."
Tisdale continued: "The facts are he was free to walk away in a few months time and he could sign a pre-contract with another club, even if he's still on contract with us.
"There were a lot of clubs trying to sign him on a pre-contract for a free transfer."
League One leaders Brighton are known to be one of the clubs who tried to bring Harley in before he decided on a move to Swansea.
Tisdale said: "You're either going to be a selling club, which we are generally, and so when we make a bold decision and decide to keep a player, you can't then grumble about it.
"I made that decision - it's my decision, no-one else's - and the club have backed me on it."
I'd rather we got 400k for him and just let him go rather than having him for 5 months
Scott Browning
With Harley having already netted eight goals for the Grecians this season, Tisdale is hoping for more of the same from the talented midfielder.
"He's one of our star players, if not our star player this season," he added.
"I'm more than happy, it's my decision, and the club has supported me all along."
"Ryan's happy knowing his future's secured and he's happy to continue playing for us knowing that's happened."
Source: BBC Sport
Source: BBC Sport