My husband left us and I didn't file for divorce or child support for over 10yrs. Once I did child support was court ordered. Can I file for the 10yrs before the court order was placed?

ANY question on law needs to include your general locale as laws vary by area.

Some areas do allow for retroactive support, most don't. Most order support starting from when the request was filed. Even where retroactive support is allowed, its up to the court whether its necessary. You would probably need to show extreme financial hardship.