Headlines collided throughout the 40s and 50s, blaring news of World War II, while acquisition of new buildings at CIM and performances by distinguished faculty and students continued in Cleveland. This period was one of major growth for the Cleveland Institute of Music, surviving the depletion of its own forces to the war effort but burgeoning beyond its very walls, necessitating the eventual construction of CIM's present site (11021 East Boulevard in University Circle) at the end of the 1950s.
"We can keep the fiddles tuned and lick the Axis, too," yelled The Plain Dealer in January 1942. Off to war went Joseph Knitzer, chairman of the violin faculty, and students Seaman First Class Harold Fink, Sergeant Starling Cumberworth, Technical Sergeant Fred Popper, Corporal Reuben Caplin and Private Fred Koch ("I'm a bugler. Yes, I'm fast becoming the hated man of the battery."). "War breaks up noted two-piano team" - Captain Beryl Rubinstein proceeded to coordinate the musical activities for the U.S. Army's Fifth Service Command, and Captain Arthur Loesser left the Institute soon thereafter.
In 1941, CIM moved from its quarters at 2605 Euclid Avenue to the Jacob D. Cox residence at 3411 Euclid Avenue. Recitals were held in the newly-constructed Willard Clapp Hall (named for the first president of the Institute), and Martha Sanders Hall arose from a converted carriage house in 1950. The house was deeded to the school in 1947 by Mr. Cox, his sister, Mrs. Cox Morrill, and her three children as a memorial to their mother and grandmother, Ellen Prentiss Cox. Mr. and Mrs. E.J. Kulas were major contributors with the Cleveland Foundation, the Louis D. Beaumont Trust and Radio Station WGAR.
Ward Lewis, theory faculty member, became dean in 1942, and upon Rubinstein's departure became acting director in 1943. Heads of departments during the war years included noted performers Leonard Rose, cello, and Leonard Shure, piano. The National Association of Schools of Music approved the Institute for graduate work in 1942.
By September 1945, CIM had reached its silver anniversary, which The Press described: "The Cleveland Institute of Music - now celebrating its 25th year - casts its long radiance not just over the city's music, where it has a pre-eminent place, but over the whole intellectual life of the community." Ward Lewis, who was on leave of absence, radioed greetings over the BBC at the special concert that featured Beryl Rubinstein performing the Chopin Scherzo in C-sharp Minor, the same work that had been performed at the opening concert of the Institute. "Today the institute has 1,000 students. That's quite a jump from the initial seven who made up the enrollment nearly a generation ago."
With the GI Bill in force, registration at CIM swelled the halls with students. Ten were added to the faculty in 1946, including Irvin Bushman, voice; Marcel Dick, theory; George Goslee, bassoon; James Ceasar, violin; and Maurice Sharp, flute. With 50 GIs in 1946, crucial building additions were necessary in 1946: new studios in the basement and on the third floor; a musical reference library, record collection and record-lending service; classrooms and practice studios. By the 1949-50 school year, the Institute had 919 students with 114 pursuing Bachelor and Master of Music degrees; 51 faculty members (14 Cleveland Orchestra personnel); and a music library with 3,904 items and 306 albums in the Kulas Record Library.