Speaking to the Herald, he said the 35-year-old (left) could have moved to Ochilview as early as last year.
"It was one that was actually in the plans from last season,” he explained. “We’ve been talking for a long time and, last summer, St Johnstone offered him a one-year deal and he decided to give it another go.
"Just through having a few injuries bothering him, I think he knew he really wanted to try out part-time football and see if that would be the best option for his body.
"He doesn’t want to retire and he wants to still play football, so it is a move that suits both parties."
The midfielder picked up a cup double with the Perth side the previous season to add to his illustrious career highlights and Swift says he comes to Stenhousemuir not looking to wind down.
"The first thing Craig said to me is he is coming here because we want to achieve something,” he said. “We ticked a few boxes in that respect because we are an ambitious football club that wants to get out of this division.
"He has really bought into what I want to do and I am sure he can do the damage. Having him in the group will be a bonus too because our younger players will be able to learn from him.”