The school was led by its first non-Christian Brother headmaster, Mr Kieran Fouhy, for 27 years from 1989 until 2015 (by far the longest tenure of any headmaster). Under his leadership, the student roll at St Peter's increased from 669 in 1989 to 1344 students in 2015. He was also responsible for the completion of significant building projects. During the 1990s, as well as the renovation (and naming) of the Brother J. B. Lynch Science Laboratories, the Brother P. C Ryan sports pavilion replaced the original pavilion built in 1960 and which had been ruined by fire. The Brother W. R. Smith Music and Drama Suite was built. Brother Smith (1948–1953), the third headmaster of the college, had initiated the first school orchestra. The Brother L. H. Wilkes Technology Block was opened in 2001 (awarded the NZIA Resene Supreme Award for Architecture 2002 and the NZIA Resene Branch Award for Architecture 2001) and a dedicated building for the intermediate school ("the Middle School") on Mountain Road, named after Brother V.A. Sullivan, was occupied in 2003. The St Peter's College Sports Complex was erected on the old netball courts and was a 2012 Auckland Architecture Award winner. In 2015 a 12-classroom block named the "Outhwaite Building," after Isa Outhwaite, the donor of the school site, was completed on Mountain Rd.