Always enable Smart Quotes in TextEdit?
TextEdit saves the state of that switch in each document, apparently; so to get round that you need something along the lines of this - Applescript Won&#39;t Invoke Shortcut Command - to test for it each time [The link contains a lot of 'live' research &amp; guesswork, but the last answer at https://apple.stackexchange.com/a/209219/85275 is the one that finally nailed it]

Using that as a base, try this…

tell application "System Events" to tell process "TextEdit"
    set v to (value of attribute "AXMenuItemMarkChar" of menu item "Smart Quotes" of menu 1 of menu item "Substitutions" of menu 1 of menu bar item "Edit" of menu bar 1)

    if v = "✓" then
        click menu item "Smart Quotes" of menu 1 of menu item "Substitutions" of menu 1 of menu bar item "Edit" of menu bar 1
    end if
end tell


You could save it as a Service &amp; invoke with a key command.

Late thought:
Make sure you are working on an rtf document, not plain text, as you have the pref set to only be 'smart' in rtf.