Ipso facto, US court orders are only enforceable in the US and US jurisdictions. However, there are a variety of international treaties and conventions that give theoretical super-national force to a variety of nations' court orders for specific purposes, such as INTERPOL, the WTO, NAFTA, etc. It really depends on the nature and scope of the court order.
In the event that a US court order is held unenforceable somewhere, diplomatic pressure can sometimes be applied, but only in cases of extraordinary national-level interest.