[4] He graduated from New Jersey's Point Pleasant Borough High School in 1979,[4][5] where he wrestled[6] and played football,[7] and earned a U.S. Army Student Achievement Award.

[10] While attending New England Law Boston, he earned two American Jurisprudence awards (in trial practice and wills, estates and trusts) and was designated a Board of Trustees Scholar after his second year.

[10] Upon entering active duty as a Judge Advocate General officer, Kirschner completed his first tour as an Army prosecutor at Fort Richardson in Alaska.

[10] After three years in that assignment, Kirschner was transferred to the U.S. Army's Legal Services Agency in Falls Church, Virginia, where he served as a government appellate attorney handling criminal appeals of court-martial convictions.

[12] After a few early rotational assignments, Kirschner joined the U.S. Attorney Office (USAO) Homicide Section, led at the time by Robert Mueller.

[21] In mid-September 2020, Kirschner argued that President Donald Trump should be charged with manslaughter for deaths resulting from him intentionally lying to the American public about the danger posed by COVID-19 virus during the COVID pandemic.