Attorney Bios

Mark D. Oldenburg, Partner

Mark D. Oldenburg's law practice focuses on business litigation and providing general business advice to a variety of clients.  He assists individuals in the formation and incorporation of new businesses and he works with a variety of small businesses in the drafting of various documents, including purchase and sale agreements, real estate documents, and employment related agreements. His litigation work includes representation of individuals and businesses, including self-insureds, in business disputes, personal injury litigation, contract disputes, and employment and construction litigation. 

Mr. Oldenburg has been involved in trials and appeals in federal and state courts, including superior, state, probate and municipal courts in numerous counties in Georgia.  He is admitted to practice in the United States Court of Appeals for the Eleventh Circuit, the United States District Court for the Northern District of Georgia, the United States District Court for the Middle District of Georgia, and all state courts in Georgia.  In addition, having completed the required training, Mr. Oldenburg is registered as an arbitrator with the Supreme Court of Georgia.  Mr. Oldenburg has an AV rating from the Martindale-Hubble Law Directory which indicates his legal ability is “from Very High to Preeminent” and his ethical standards rating is “Very High.”

In 1994, Mr. Oldenburg was appointed a Special Assistant Attorney General by the Attorney General of the State of Georgia and in that capacity represented the State of Georgia Department of Administrative Services.  In the course of representing the Department of Administrative Services he assisted in developing the program to prosecute that department's workers' compensation subrogation claims and was involved in over one thousand such matters.  Mr. Oldenburg has also received separate appointments as a Special Assistant Attorney General to assist the Georgia Department of Community Health, Division of Medical Assistance with its administrative hearings and subrogation claims and he has been doing so since 1995. Additionally, Mr. Oldenburg has been appointed as a Special Assistant Attorney General to assist the Georgia Department of Natural Resources, Environmental Protection Division with some of its collection actions.  Mr. Oldenburg served as the attorney for the Peachtree City Development Authority from 1997 through 2004 and has served as the attorney for the Peachtree City Water and Sewerage Authority from 1999 to the present. 

Mr. Oldenburg grew up in Charlotte, North Carolina and attended Davidson College in Davidson, North Carolina, where he received an A.B. in 1983.  In 1986, he received a J.D. from Wake Forest University School of Law in Winston-Salem, North Carolina.  While at Wake Forest he was elected to the Moot Court Board and was a member of the three-person National Moot Court Team.  He was also selected a National Member of the Order of Barristers for exhibiting excellence and attaining high honor through the art of courtroom advocacy.  He practiced with the firm of Greene, Buckley, DeRieux & Jones in Atlanta, Georgia from 1986 through 1989 where his practice focused primarily on trial work involving tort and insurance litigation.  He worked with the firm of Chamberlain, Hrdlicka, White, Williams & Martin in its Atlanta office from 1989 through 1995 and developed a business litigation practice while continuing his representation of self-insureds.  From 1995 through February, 1997, he practiced with the firm of Webb & Lindsey in Peachtree City, Georgia.  He started his own law firm on March 1, 1997.

Mr. Oldenburg is a member of the State Bar of Georgia, the Atlanta Bar Association, the Fayette County Bar Association and the Atlanta Claims Association.  He has volunteered time with the Atlanta Volunteer Lawyer's Foundation. Mr. Oldenburg and his family have lived in Peachtree City for over twelve years.  He has enjoyed coaching his sons in basketball, soccer and baseball.

Gary V. Stiner, Jr., Partner

Mr. Stiner is a native of Tennessee and graduated magna cum laude with a Bachelor of Science in Business Administration from the University of Tennessee at Chattanooga in 1997.  He obtained his Juris Doctor degree from the University of Georgia School of Law in 2000.  Prior to joining the firm in 2004, Mr. Stiner clerked for the Honorable W. Fletcher Sams in Fayette County State Court.  Mr. Stiner also clerked for the Honorable Henry M. Newkirk in Fulton County State Court while attending law school.

Before entering law school, Mr. Stiner gained valuable business experience working in the insurance industry and as a location manager for a national retail chain.  Mr. Stiner’s management experience and his background in public service with the state courts has afforded him a unique perspective on the needs and goals of the Firm’s business clients.  Mr. Stiner’s practice focuses on construction law, contract law, real property law, personal injury litigation, landlord/tenant disputes, and litigation involving the Georgia Department of Community Health.

Mr. Stiner is admitted to practice before the United States District Court for the Northern District of Georgia and before all Georgia State Courts, including the Supreme Court.  He is a member of the American Bar Association, the Georgia Bar Association, and the Fayette County Bar Association.

Heather M. Loridas, Associate

Ms. Loridas began her legal career in Ohio where she graduated from the University of Dayton with a Bachelor of Arts in Psychology in 1998. She obtained her Juris Doctor from the University of Dayton School of Law in 2001 where she was a member of the Moot Court Honor Society competing in the Corporate Law competition in Wilmington, Delaware. While in law school, Ms. Loridas clerked for the Honorable David Gowdown in the Montgomery County Common Pleas Court.

After graduating from law school, Ms. Loridas joined a large civil litigation firm in Dayton, Ohio where she focused her practice on medical malpractice defense, business litigation and general tort litigation from 2001-2007. In 2006 and 2007, Ms. Loridas was named an Ohio Super Lawyers Rising Star by Law & Politics magazine and in 2006 was awarded the honor of Who’s Who in the Law by the Dayton Business Journal.

Ms. Loridas spent four years on the Associate Board of the American Red Cross, serving as President of the Associate Board in 2004 and receiving the Associate Board Member of the Year award in 2006. She has also raised money for The Leukemia & Lymphoma Society through Team in Training where she participated in two marathons; and for the Susan G. Komen Foundation where she completed the sixty-mile walk for breast cancer research in 2003 and 2006.

In 2007, Ms. Loridas and her family moved to Georgia. She joined the firm of Flint & Adler where her practice focused on medical malpractice defense, civil rights defense and business litigation. In September 2008, Ms. Loridas joined the firm where she is focusing her practice on general civil litigation matters.

Ms. Loridas is admitted to practice law in the United States District Court for the Northern District of Georgia, the United States District Court for the Middle District of Georgia and all state courts in Georgia. She is a member of the State Bar of Georgia, the Fayette County Bar Association and the American Bar Association.

Rachel M. O'Toole, Associate

Ms. O’Toole has repeatedly been acknowledged by her peers as an accomplished attorney, dedicated and committed to providing the highest level of individual care and attention in the representation of her clients.


Ms. O’Toole trained at the Honourable Society of Kings Inns to achieve her Barrister at Law degree and remains a member of the Bar Council of Ireland. During her training at the Honourable Society of Kings Inns, Dublin, in 2011 Ms. O’Toole was awarded a scholarship to study Accelerated Trial Advocacy Skills at Chicago’s John Marshall Law School.  In 2015 Ms. O’Toole was recipient of the Dean’s Fellowship at the Georgia State University College of Law to study for her specialized LL.M.

In 2009 Ms. O’Toole earned a B.A. in English Literature and Legal Science from the National University of Ireland.  The following year she was awarded her LL.B. (the equivalent of a J.D. in the United States) with honors.  She received her specialized LL.M, Suma Cum Laude in 2016.

After relocating to the United States she passed the California bar in 2014, as well as the Georgia bar in 2015.  Ms. O’Toole has been admitted to practice law in the Superior Courts of California, the Superior Courts of Georgia, the Court of Appeals and the Supreme Court of Georgia.  She is also admitted to practice law in the United States District Court for the Northern District of Georgia. Ms. O’Toole remains admitted to practice law in all the courts in Ireland.

In 2015 Ms. O’Toole joined Oldenburg & Stiner P.C.  She is a member of the State Bar of Georgia, the Fayette County Bar Association, the American Bar Association, State Bar of California and the Bar Council of Ireland.  She is registered as a neutral in General Civil and Domestic Relations Mediation with Georgia Commission on Dispute Resolution.

Ms. O’Toole is an avid hiker and loves outdoor activities.  She is an expert in woodcarving and woodwork.  She is also a keen painter.  But her passion is all aspects in the field of law and provision of excellence in service to her clients.