My husband went to NJ (we live in PA) for an internship but he went back before the end of the year. What is his residency?

[zizi]

I am a resident alien with H1B and my husband is a non-resident alien on F-1.
We are living in PA and we decide to file jointly. He went to NJ last year for three months for an internship (September~December 15th). He came back before Dec 31 2018.  

Since he is back in PA before December 31 2018, is his residency PA? If so, after putting NJ as another state he lived in Turbotax, Turbotax is asking the date he became a resident of PA, what date should be put?

[KarenJ]

If he was living in PA on January 1, 2018,  you should enter that date or the date he first moved to PA.  You should prepare your NJ nonresident return first in TurboTax so the software can calculate the amount of credit he will receive on your PA tax return for his tax liability in NJ. 

[zizi]

Thanks for replying! I still need to prepare my federal first, right? Then NJ, then PA?