A complete search of the internet has found these results:
After he finished school is the most popular phrase on the web.
These phrases have the same meaning but are in different verb tenses. "After he finishes school" refers to something that will happen in the future. "After he finished school" refers to an event that already happened.
25,700 results on the web
After he finished school, we'd meet in Central Park.
Your father started teaching after he finished high school.
I trained newly blind people for ten years after I finished school.
I was going to take Regan to Europe for a while after she finished school.
And when he finished school... deserted you and went home.
What did his mother do with her days after he finished school and went to college?
After they finished school, they all went their different ways to live their own separate lives.
What did Charlie do after he finished school last spring?
13,800 results on the web
Maybe he plans on taking up prizefighting after he finishes school this year.
Just after he finishes talking to my daddy, I guess.
Charlie and I are going camping tomorrow at Juniper Park after he finishes his shift.
Yeah. Right after he finishes everything on the bride's to-do list.
And Nurcan's going to work when she finishes school.
I don't want Travis to be one of those kids that who, after he finishes school, just sits around doing nothing, waiting for his dream job.
Twenty minutes later, he finishes photographing the bedroom.
After he finishes grad school, he will work as a mechanical engineer at a company in Spain.