[2] Born in New York on June 12, 1964, O'Neil attended La Salle Institute in Troy and was selected for their Athletic Hall of Fame as a senior in 1982.

He was inducted into the Norwich University Athletic Hall of Fame in 1986 for winning the Distinguished Letterman Award in Football and Track & Field.

He planned and executed training programs to prepare his unit for missions in sensitive environments requiring sophisticated tactics, techniques and procedures.

In that role, he synchronized and integrated all assigned ground, maritime, air, and lethal and nonlethal fires during training and operations.

From June 2011 to December 2012, O'Neil served as the Executive Officer to the Chief of Staff, United States Army.