Tax Year Prior to 2020: If my dependent was in college and, had a p/t job, but we supported him does he still need to file a federal return?

IF SINGLE AND UNEARNED INCOME WAS OVER $1100 OR YOUR EARNED INCOME WAS OVER $12200 OR YOUR GROSS INCOME WAS MORE THAN THE LARGER OF $1100 OR YOUR EARNED INCOME UP TO $11850 PLUS $350.  IF NONE OF THE ABOVE APPLY AND THERE WAS WITHHOLDING, DEPENDENT SHOULD APPLY TO GET BACK THE WITHHOLDING.  

If your dependent is claimed on your tax return, they may still be required to file an income tax return of their own. The requirements vary by filing status and age. 

So long as you are responsible for more than half your child's support and is below the age of 24 years, you can file for your child as a dependent and your child in turn can file to receive a refund for his or her federal taxes. Only if the child is filing just to receive a refund is he or she allowed to file a joint return.