establish (oneself, someone, or something) as (something)
To confirm oneself, someone, or something's role or reputation as being a certain thing or having a certain status. That merger established the company as the biggest on the East Coast. I think you need to establish yourself as a tough teacher early on so that the kids actually listen to you.
establish someone or something as someone or something
to validate or confirm someone or something as someone or something. As soon as we establish her as a viable candidate, we will launch the publicity campaign. She established herself as an authority on rare books.