Can I enforce an English judgment in US?

Yes, but you have to domesticate the judgment, i.e. convert it into a New York judgment, just as you have to domesticate any judgment from another state.  The process for doing so is not that complicated if the case out of which the judgment arose was defended.  If the judgment was on default, you would have to start a new lawsuit in the US, but the judgment would be conclusive unless the defendant can show that the English court lacked jurisdiction over him/her/it.