John's career in public service began in the military, a three year active duty tour as a JAG Corps officer with the U.S. Navy during the Vietnam War. His primary duties were as trial (prosecuting) and defense counsel in dozens of courts martial. From there, he worked in a civilian capacity as an attorney-advisor specializing in contract and procurement law for the Kansas City District of the U.S. Army Corps of Engineers. His success there led to his promotion to a position as a labor laywer and senior litigator for the Kansas City Region of the Federal Labor Relations Authority, where he investigated and litigated hundreds of unfair labor practice and labor representation cases throughout the Midwest.

From the FLRA, John was chosen from among 78 applicants to serve as Assistant Regional Counsel at the Kansas City Regional Office of the Federal Bureau of Prisons, and attorney-advisor at the U.S. Penitentiary in Leavenworth, Kansas. He qualified for this position by completing a physically rigorous and mentally challenging self-defense, weapons firing range, and classroom training course at the Federal Law Enforcement Training Center in Glynco, Georgia, graduating first in the class and voted class valedictorian by his peers. His duties at the Bureau included defending Bureau employees, especially corrections officers, and the Bureau itself in civil rights, tort claims and other litigation filed primarily by inmates. From correctional law, John next rose to a position as a banking law specialist and a senior litigator for the Kansas City Region of the Federal Deposit Insurance Corporation. There he prosecuted financial institutions and their officers who engaged in unsafe or unsound banking practices or violations of banking laws and regulations in seven Midwestern states. His superior accomplishments there resulted in his appointment as the Regional Counsel of the FDIC's Atlanta Regional Office, where he headed a large legal staff with responsibility for legal compliance and enforcement supervision of all FDIC-insured banks in the southeastern U.S.

Based on his long record of exemplary Federal service, in October 1994 John was appointed by the Secretary of the Department of Health and Human Services as a United States Administrative Law Judge, and he served in that capacity with the Social Security Administration in Kansas City for ten years until his retirement. He presided at administrative hearings and issued final written decisions in some 3000 Social Security disability, retirement, Medicare, and related cases. In 2001-2002, Judge Rubin also served as Regional Vice-President of the Association of Administrative Law Judges, the union which represents Social Security ALJs.

Since his retirement from the Federal bench in 2004, Judge Rubin has worked an an arbitrator for the Financial Industry Regulatory Authority (formerly the National Association of Securities Dealers), adjudicating complaints filed against securities industry brokers/dealers by their customers or employees. He also has been active in community service, volunteering his time and talents as an actor in numerous community theatre productions presented in venues ranging from Shawnee Mission Theatre in the Park, Leawood Stage, Longview Community College, The Barn Players, and the Olathe Community Theatre, to Senior Barn Players shows presented to civic and church groups, and to shut-ins in retirement communities and nursing homes who otherwise would be unable to experience artistic presentations.

John is a member of the Missouri, Kansas and Federal Bars and the American Legion. He is past president of the Woodland Place Homes Association. He attends St. Joseph Catholic Church in Shawnee. He has been married 35 years to the former Roberta Torin, MSW, of St. Louis, Missouri. They have two adult daughters and one granddaughter.