An Arlington, Virginia, native, Koomey was a three-year varsity starter at Yorktown High School, where he was named Team MVP his junior and senior year. He was also All-Conference First Team as a senior. Now, he pitches for Rensselaer Polytechnic Institute, recording a 3-2 record this past season in nine appearances. Academically, Koomey has made the Dean's Honor List and is working on a dual major in aeronautical and mechanical engineering.