First, you do want to check your color space for Photoshop and the photos you are working on. The safest thing is to have everything in the sRGB color space, so if these are pictures you are shooting, check your camera and make sure it is set to the sRGB color space. Then, in Photoshop, use your Color Preferences dialog to make sure that Photoshop is using sRGB, and that Photoshop converts files to sRGB on opening them.
You say that sports and event shots come out fine, but portrait-type shots don't, and I'd suspect that two cameras are being used with two color space settings. So you can compare the camera setting to see if that might be true. Picture Style settings can certainly affect the contrast and saturation of jpegs, but that would show in Photoshop as well.
Try opening one of the "good" sports/event photos in Photoshop, and opening one of the "hot" photos as well, and on each, open the Edit/Convert to Profile dialog and see if you can see any differeces, as in is the source profile identified in a different way (either a non-sRGB profile or no profile at all in one of them).
Finally, you should know that if you monitor is not properly calibrated/profiled, all bets are off. Photos will display differently in different apps and nothing can be considered "accurate". So, monitor calibration is always a good place to start.