The organ is the second to be installed in the present church building and was given in 1952 as a memorial by 290 members of the parish. It was designed by Edgar Hilliar, long-time music director of St. Mark's.
Opus 1201 was built by the Aeolian-Skinner Organ Company of Boston. It is a three manual and pedal instrument and is one of the first organs with a 'double' swell. It is also one of a handful of organs bearing a G. Donald Harrision 'signature' plaque.
During 2002 and 2003, in celebration of its fiftieth year of continuous use, funds were raised to recondition the organ and moderinize the console and electro-mechanical components. At that time several digital stops were also added. The work, carried-out by the Southfield Organ Company, was completed in 2004.