If you press v during viewing file with less utility, it'll open an editor.
You can choose the editor by setting LESSEDIT variable. For example:
export LESSEDIT='subl %f'
Standard VISUAL and EDITOR variables usually have this covered.
@dmedvinsky They probably don't accept such parameters as %f
@sheerun True, but %f isn't interesting, it is passed anyway so that file is opened. What might be interesting is %lm or %lt. In case you want to use them, then yes, LESSEDIT it is.