Could a foreign j1 visa holder marry a US citizen in their home country and then return to the US with their US spouse immediately?

I used to work with J-1 visa applicants from France. I can help you analyse the your question more deeply and can offer an assumtion but not a definitive answer. For that, I suggest you visit your local US Consulate or Embassy. Does your country, the country where you would be married and of which you have citizenship, have an agreement with the US which permits you to visit the US as a tourist without a visa, that is, to travel in the US only on your passport? If so, it seems to me that your J-1 visa has nothing to do with your returning to the US as a tourist for up to 3 months, usually. You cannot however, as I understand it, apply immediately for a new J-1 visa upon the expiration of your present J-1 visa. However, I think that you must report to the American Consulate in your country in oder to inform them and to declare your marriage and could probably apply for a long term residence permit as the spouse of an American at that time. As for getting married to an American just to obtain US citizenship, it is frowned upon and I think illegal. Doing so might cost you the chance of obtaining an American residence permit and ever residing in the US if proven. If that is what you intend, why not simply apply for a green card? Depending on your country of residence, there is a fairly large quota of those available at this time, I understand. For information about a green card, go to: www.us-green-card-lottery.org