Of course a professor has control over the admission process. If he wants you on his team, you're in, unless you have a criminal record, or GPA below 3.0 (or whatever is absolute minimum for that particular grad school).
Think of it as a hiring process, with the professor as a hiring manager.
Based on the conversations I have had, it seems to be typical that a committee selects the applicants, not the professors. That is what all the professors tell me.
That being said, I would be stunned if this were the truth. There is no frickin way that this happens. Here's how I imagine it:
'Admissions committee is in session'
'So, which of these bozos we gonna pick?'
'I want Joe, Schmo, and Dingus'
'Sweet, I want Harry, and Fiona'
'Ok, we all cool?'
'Yep'
'Aite, lets get beers'
Well, the committee also has a job of selecting the rest of the applicants, if there are still places left after professors made their recommendations.
Of course a professor has control over the admission process. If he wants you on his team, you're in, unless you have a criminal record, or GPA below 3.0 (or whatever is absolute minimum for that particular grad school).
Think of it as a hiring process, with the professor as a hiring manager.