since his childhood
Das macht Tom schon seit seiner Kindheit.
Tom has been doing this since he was a child.
Tom lebt schon seit seiner Kindheit in New York.
Tom has lived in New York since he was a child.
Ich kannte Chris Reilly seit seiner Kindheit.
I've known Chris Reilly since he was a child.
— The Wind That Shakes the Barley (2006)
Er war seit seiner Kindheit zierlich.
He had been slight since childhood.