Pavlik is stepping down after 15 years of service, in which time he has been the only communications chief in the Academy's history.
He had earlier served stints as the Academy's executive administrator from 1979 to 1982, and as director of the five-year endowment campaign for the Academy's Margaret Herrick Library between 1989 and 1993.
Unger, currently the organisation's publicity coordinator, joined the Academy staff in 1992.
'This is no minor change for us,' the Academy's executive director Bruce Davis said. 'John has been a key part of the Academy staff for a good long while, and his knowledge, his wide network of industry relationships and his fabled grace under pressure won't be easily replaced.
'The good news, of course, is that Leslie has had a chance to study him at close range for almost 15 years now, and our executive administrator, Ric Robertson, and I have no doubts that she'll make a seamless transition into the top job.'
Unger will assume her new position on Apr 1.