"previous intern" is a correct and usable phrase in written English.
One example of its use would be: "We hired her for the position based on her excellent performance as a previous intern."
Prospective interns should ask supervisors to describe the projects to which they will be assigned and chat with previous interns before making a decision.
However, just a third of graduate intakes are comprised of previous interns, so there are plenty of graduate jobs that don't go to interns.
It has been said that studying abroad can give applicants an edge in the job market, but more than likely an employer would rather see previous interning and work experience listed on a candidate's resume.
Similarly, a previous editorial intern filed a lawsuit against Charlie Rose, after feeling her time spent at the television talk show violated labor laws because she didn't receive training and was unpaid.
Ohlendorf had spent a previous winter as an intern in the finance office of the University of Texas system.
Paris-based Arquilliere, a recent student and a previous product marketing intern with Google, launched an experimental version of ZenTracker a few weeks ago, based on the limited public API of Latitude.
She was just 21 and had spent the previous two summers interning at NASA.
Mr. Deegan, who had spent previous summers as an intern at the Putnam County historical society, wheedled his way onto Mr. Martin's crew through sheer force of enthusiasm, and his first job seemed typically menial: clearing dirt and leaves.
The response rate was very high and the survey includes considerably more interns than previous studies.
