A valid judgment in one state is enforceable in the other 49 states under the Full Faith and Credit Doctrine of the U S Constitution.

If the judgment is a judgment after trial, it is usually simply a matter of getting a verified copy of the judgment from the court that rendered judgment, and filing it with the court of the state in which it is to be enforced. It then becomes a judgment of the court in the enforcing state.

In the case of a judgment after default, most states require that there be a second trial in the enforcing state. The main question before the court in the enforcing state is whether the court in the original forum state had proper jurisdiction over the defendant. If so, judgment is then entered against the defendant, and is enforceable. This trial is usually an expedited process, and there are few defenses available to the defendant other than jurisdictional challenges.

Each state has its own procedure for enforcing both of these types of foreign judgments from other states, and it is usually best to get an attorney involved in it in order to make certain that the state's laws of civil procedure have been observed.