John Hagstrom joined the Chicago Symphony Orchestra as a member of its famous trumpet section in 1996. He is also in constant demand as both a trumpet teacher and trumpet soloist around the world. Prior to joining the Chicago Symphony Orchestra, he had been the principal trumpet with the Wichita Symphony Orchestra and "The President's Own" United States Marine Band, in Washington, DC.

Hagstrom is also passionate about music education, and helped to initiate Dream Out Loud, a music education advocacy partnership between the Chicago Symphony Orchestra Association and the Yamaha Corporation of America in 2007. Dream Out Loud, which was created for elementary through high school students, their teachers, and their parents, offers a variety of resources designed to support every student's interest in playing an instrument and provides encouragement through times of challenge.

Hagstrom has also worked extensively with Yamaha to create several professional trumpet designs in its Chicago Artist Model Series that include top selling Bb and C trumpets. Since its introduction in 2004, the Chicago Artist Model C Trumpet has been the instrument played most often by those who have won orchestral positions in major U.S. orchestras.

Due to its phenomenal commercial and artistic success worldwide, in 2006 Yamaha selected the Chicago Artist Model C Trumpet to be its 10 millionth instrument ever produced. Hagstrom has also worked with Yamaha to design a C Cornet (YCR-9435), a Custom Eb/D Trumpet (YTR-9636), a Custom Bb/A Piccolo Trumpet (YTR-9825), and the new Chicago Artist Model C Trumpet (YTR-9445CHSII).

In June of 2006 John Hagstrom's first solo CD was released on the Albany Records label. Time Out Chicago commented, "You'd never guess he was a mild-mannered second trumpeter from the hair-raising high notes... or from the way he seamlessly unfurls long lines." The International Trumpet Guild Journal said, "Hagstrom is, without a doubt, a brilliant trumpet player with the elegance of sound consistent with the Chicago Symphony Orchestra's distinguished history of brass playing."