The gradient overlay is a useful tool to add spice to a dreary canvas. Like most things in Photoshop, the secret is how to use the tool to get it to do what you want. Here’s one secret to moving a centered Radial.
Start with a standard radial gradient. This one was made using a gradient overlay to a layer using the FX button on the layers panel. And they “style” of the gradient is Radial.
The Radial Gradient by default is centered over the canvas. The trick is to expand the canvas of the layer while hiding it out side of the image. We start by dragging the layer down or up so that we can paint in the area of where we want the gradient to move towards.
Painting a small amount will move the gradient over just a bit. Paint more and the gradient moves more. Gone too far? Erase some of the paint and watch the gradient move back.
Now move the layer to hide all the new paint you’ve added. Now the gradient is just where you wanted it to be!