Your laptop would probably be outputting the 23fps (actually closer to 24fps) video as 1080p60: this would result in judder because 23/24 doesn't go into 60 evenly.
It is highly unlikely your TV would be able to convert the 1080p60 input back to 23/24fps (and then internally multiply that evenly to 120Hz) to reduce the judder.
However, if you were to output 1080i60 from your laptop (interlaced, not progressive), your TV might have the ability to convert it back to 1080p24 internally.
When you play the 23/24fps video directly on the TV, I expect it retains the original 23/24fps and so is able to smoothly multiply that to 120Hz.
Your problem is the conversion that the laptop is doing, because 60Hz is a VGA standard.
As someone else mentioned, if you can output HDMI via a DVI->HDMI adapter from the laptop to the TV and set the laptop refresh to 24Hz, you will probably notice less judder.
If you can't do this, I would suggest trying 1080i60 output from the laptop and see if the TV has a feature to convert that back to 23/24fps for display.