In 1978 she was selected as an Outstanding Young Woman in America in recognition of outstanding ability, accomplishments and service to the community. She completed course work in accounting at Roosevelt University, Chicago, Illinois, during 1981 through 1983 and passed the Uniform Certified Public Accountant (CPA) Examination in 1985. She is currently licensed by the State of Pennsylvania Certified Public Accountancy Board.

She was appointed Postal Inspector in October 1978 and assigned to the Chicago Division, recently renamed the Northern Illinois Division. While in Chicago, she worked a variety of investigations but was primarily assigned to External Crimes and Audit. In May 1985, Ms. Gillis was promoted to Program Manager, Central Region, Chicago, Illinois.

In January 1987, she was selected for the Postal Service Career Executive (PCES) candidate list. Ms. Gillis was promoted to Inspector in Charge, Hartford Division, U S. Postal Inspection Service, November 7, 1987, and in February 1988 she attended the Fuqua School of Business Executive Program at Duke University.

Effective April 1989, Inspector Gillis was promoted to Assistant Regional Chief Inspector Eastern Region, a PCES position. She attended a training program for Postal Executives in August 1989 at the University of Virginia.

In May 1993, Ms. Gillis was appointed to Inspector in Charge, Washington Division.

On July 5, 1994, Ms. Gillis was appointed to her current position, Inspector in Charge, Northern Illinois Division, Chicago, Illinois. The Northern Illinois Division has a complement of over 260 employees, which includes Postal Inspectors, uniform Postal Police Officers and administrative support personnel. Her geographic area of responsibility includes the State of Illinois covered by the U.S. Postal Service, Great Lakes Area.

As the Inspector in Charge, Northern Illinois Division, she is responsible for the overall management of all programs, projects, investigations and reviews which include but are not limited to external crimes, internal crimes, mail fraud, security and fraudulent investigations such as workers compensation.

She received a one year sabbatical August 2000 - July 2001 to serve as the President/CEO of the National Organization of Black Law Enforcement Executives (NOBLE). She is also an active member of Alpha Kappa Alpha Sorority, Inc., and a member of the Zion Progressive Baptist Church.

Since September 2001, Inspector Gillis has been detailed to the position of Deputy Chief Inspector, Professional Standards and Resource Development. In this capacity, she operates autonomously in overseeing and directing the major functional areas under her responsibility which includes finance, human resources, strategic planning and training for the Postal Inspection Service. She is a direct report to the Chief Postal Inspector and is accountable for leading, guiding, supporting and effectively measuring the performance of four executive direct reports.

Inspector Gillis has received numerous awards and recognition throughout her career. In 1997, Ida served as chairperson for the Chicago Council Boy Scouts (Explorers) of America's Annual Law Enforcement Security Luncheon and Exposition and in 1999; she received the esteemed Good Scout Award.

In October 1997, she received the U.S. Postal Service National Diversity Achievement Award. The program was established to recognize and support those individuals and teams who have made significant contributions to encourage and promote diversity within the organization. In 1998, she received the "Chief Inspector Award."