Information about the main building comes from http://www.fortwortharchitecture.com/north/eldermiddle.htm:
North Side Junior High School opened in 1927, just to the north of the North Fort Worth High School (1918), and across the street from the Circle Park Elementary School (1908; demolished).  It was designed by Fort Worth Architect Wiley G. Clarkson and it was constructed by Butcher and Sweeney.  The building is three stories with polychrome brown brick.  The main facade is symmetrical and features a central and projecting entrance element.  The elements of the entrance reflect a Tudor styling that is carried throughout the front facade of the building.  Unfortunately, the windows have been partially infilled, typical of many of the FWISD historic school buildings.  In 1935, the school was renamed for John Peyton Elder, who was a superintendent of Swift & Co. Elder also served on the Board of Education and the Fort Worth City Council.

J.P. Elder Middle School has two brick buildings: the Annex and the Main building.  Both buildings are three stories high. Built in 1918, the Annex is in the National Register of Historic Places and was saved from demolition in the mid-1900s.  It was originally a high school but was taken over by J.P. Elder Middle School in 1955.

John Peyton Elder
The following was written by the family of John Peyton Elder and is reprinted in its entirety.

"John Peyton Elder was born in Fairfield, Missouri, on August 18, 1872.  He was the son of Dr. and Mrs. James A. Elder.  His early years were spent on a farm in Missouri while attending the country school there. His first job was with a man's clothing store while he studied bookkeeping.  In 1904, he joined the Pacific Coast Borax Company and traveled extensively driving the Twenty-Mule Team as an advertising stunt. Many years later, there was a popular television series entitled, "The Twenty Mule Team Borax," which featured the adventures of the mule team as it traveled the country.  As Mr. Elder traveled the country, he made a stop over in Avery, Texas, and rented a room at the Roberts Hotel.  At the hotel, he met Nannie Lou Roberts, who was to later become his wife. In 1906, he married Nannie Lou and moved to Fort Worth the following year.  In September of 1907, Mr. Elder began working for Swift and Company, a major meat packing plant on the North Side of the city.  He was a dedicated employee and rose quickly with the packing plant. In 1915, Mr. Elder became Superintendent of Swift and Company.  While serving as Superintendent of the Fort Worth plant, Mr. Elder also served the community as a civic leader. He served on the Board of Education for the Fort Worth Public Schools for 10 years from 1920 - 1930.  During that time, he served as Vice President of the Board.  In 1935, Mr. Elder was honored to have the North Side Junior High School named for him. The board president at the time said, "We value highly the association with you and the resultant friendship.  Every member of the Board of Education considers that in honoring you by giving your name to the North Side Junior High School, he is in turn honoring the school system, in view of the many years of unselfish service you have rendered." Mr. Elder also served his community on the City Council of Fort Worth and as County Land Agent. He was a Mason and a Shriner as well.  Mr. Elder was well liked and well respected by all who knew him. He was kind hearted and thrived on helping others.  Many residents of Fort Worth held deep gratitude toward him for their employment at the large and thriving meat packing plant that was a major part of the city at that time.  He was a man of great patience, one who always had time to talk to those who sought his advice or help.  Mr. Elder retired from Swift & Co. in 1937, after 30 years of service. In Mr. Elder's leisure time he enjoyed fishing and golfing.  The family enjoyed vacationing in Eureka Springs, Arkansas, one of his favorite places to relax. During a trip to Eureka Springs, Mr. Elder suffered a fall which resulted in pneumonia.  He passed from this life on August 13, 1940, at the age of 67."