Fernie returned to Wellington in the early 1950s as the director of music for Catholic Schools in the Archdiocese, a position he held until 1953 when he was called back to London as organist and choir instructor at Westminster Cathedral.
His notable students included Nicolas Kynaston, Ivan Bootham, Patricia Lawrey, Anthony Jennings, Peter Walls, Denis Smalley, Geoffrey Coker, Roy Tankersley, Christopher Hainsworth and Barry Mora.
He was Wellington city organist for 27 years and played the Town Hall's massive Norman & Beard pipe organ on numerous occasions for civic receptions and supervised its restoration in the 1980s.
The organ was originally built in 1958 by George Croft and Son Limited from Auckland to the tonal design and pipe-scaling of Maxwell Fernie, who also supervised the voicing of the pipes and the construction of the instrument.
Tonally it might be said that the organ, with mainly pipes from England and parts from Germany, the Netherlands and United States has a Continental flavour...acknowledging all schools of composition of the various periods and nationalities.
In 1984 the instrument was extensively rebuilt and extended by the South Island Organ Company of Timaru, once again to the specifications designed by Maxwell Fernie and under his careful supervision.
An appeal launched in December 2006 raised funds sufficient to restore the organ to its 1958 performance condition and also, to replace the original electrical circuitry with a modern computerised system.