Oregon resident, work and attend school in Michigan.

[Gao37]

My son's permanent address is in Oregon but he attended college and worked in Michigan. Does he need to file taxes in both states?

[maglib]

@Gao37   Unless  your son had income from the nonresident state of Michigan, he only may need to file in his home state.

 If he had earnings from Michigan sources that exceed the Michigan exemption allowance ( Oregon is not a reciprocal state for taxes with Michigan) he would have to complete a Michigan return where he allocates his federal income to Michigan source  and then complete his Oregon return. He would get a credit for double taxation in his home state.

Michigan tax rate is 4.25% and taxpayers receive a personal exemption of $5,400 per dependent in TY 2023.

STATE INCOME TAX EXEMPTIONS
Michigan taxpayers are allowed to take a number of exemptions, depending on the number of people in
the taxpayer’s household, their ages, and other factors. These exemptions include:
• $5,400 personal exemption.
• $5,400 for each dependent.
Additional Exemptions
• $5,400 if you were the parent of a stillborn child delivered in 2023 and have a certificate of
stillbirth from the Michigan Department of Health and Human Services.
• $2,900 for each person or dependent in the household who is deaf, paraplegic, quadriplegic,
hemiplegic, totally and permanently disabled, or blind.
• $400 for each disabled veteran in the household.

Oregon 

Amounts apply to full-year residents only.
Your filing
status is:
Number of boxes
checked on line
17 of return:
And your
gross income
is more than:
Dependent Any $1,250*
Single
0 $7,305
1 $8,505
2 $9,705
Married filing
jointly
0 $14,605
1 $15,605
2 $16,605
3 $17,605
4 $18,605
Married filing
separately
0 $7,305
1 $8,305
2 $9,305
Head of household
0 $9,165
1 $10,365
2 $11,565
Qualifying
surviving spouse
0 $10,180
1 $11,180
2 $12,180
*The larger of $1,250, or your earned income plus $400,
up to the standard deduction amount for your filing status.
In addition, file a return if:
• You’re required to file a federal return.
• You had $1 or more of Oregon income tax withheld
from your wages and you want to claim a refund.
• You may qualify to claim a refundable credit.
How long will it take to get my refund?

[Hal_Al]

The standard rule applies, in your case. 

The general rule is: your report all your income on your home state return, even the income earned out of state. You file a non-resident state return for the state you worked in and pay tax to that state. Your home state will give you a credit, or partial credit, for what you paid the non-resident state. You will have to file a non resident MI state return and pay MI tax on the income earned there.. You will also file a OR full year resident return and calculate tax on ALL your income. OR will give you a credit, or partial credit, for the tax you pay MI. So, there will be little or no double taxation, but you have the cost and hassle of filing two state returns. Do the nonresident state return first.

[maglib]

https://www.michigan.gov/taxes/-/media/Project/Websites/taxes/Forms/2023/2023-IIT-Forms/Schedule-NR.... is a link to a Michigan NR return so you can see how easily you allocate income during the TT interview