The appointment, announced today by the chancellor of the University System of New Hampshire, is pending a formal vote April 20 of the system's Board of Trustees.
Steen will assume her new duties July 1 following the retirement of Donald Wharton, who has been PSU's president for the past 13 years.
Steen was named one of four finalists for the position in March.
"We're delighted for Sara Jayne Steen," MSU president Geoff Gamble said. "Her outstanding leadership ability has shown clearly in her work at Montana State University, and we expect as she moves into the President's role she will continue to demonstrate the excellent leadership that we have seen from her here.
"Of course," he added, "we are very sorry to see her go, as she has done outstanding things for her college and for MSU, but we certainly wish her the best as she assumes another challenging leadership role in higher education."
Said Steen: "I'm honored to have been recommended for the position and look forward to joining the team of wonderful people who are Plymouth State University and to having the opportunity to share in that future.
"At the same time," she added, "it's clear that Montana State University has been and is a large part of my life. It has offered a fine academic environment, and I hope to stay in touch with friends and colleagues from both the campus and the community."
Steen, whose bachelor's, master's and doctoral degrees are in English, began teaching at MSU in the Department of English in 1978. She became department head in 1996. In 2002 the American Council on Education selected her for a year-long, in-residence fellowship to study higher education administration at the University of Delaware. In 2003 she became dean of MSU's largest college, Letters and Science.
In 1996 she was awarded the President's Distinguished Teaching Award at MSU. She is a scholar of Renaissance literature and has published a number of books, papers and journal articles during her career.
"Dr. Steen's extensive background in public higher education, both as a teacher and as a senior administrator, positions her to be a very effective leader at Plymouth State University as the institution continues its transition from a college to a comprehensive regional university," said Eugene Savage, a member of the USNH Board of Trustees and chair of the search committee.
Recognized as one of the "Best in the Northeast" by The Princeton Review, PSU has 4,000 undergraduate students and 1,500 graduate students on its campus in Plymouth, N.H., according to its Web site.
Contact: Sara Jayne Steen, (406) 994-4288