Justin Krieger serves as the Managing Partner of the firm's Denver office. He is a first chair inter partes review (IPR) and post-grant review (PGR) litigator with a tremendously successful track record for challenging third party patents as well as defending against patent challenges brought before the Patent Trial & Appeal Board (PTAB). As a registered patent attorney, Mr. Krieger also focuses on client counseling, district court litigation, and patent prosecution. His technical focus includes chemistry, chemical engineering, biotechnology, medical devices, metallurgy, nanotechnology, mechanical engineering and consumer products. He has significant experience managing large domestic and international patent portfolios in these industries.

Mr. Krieger supervises a post-grant patent practice team that has consistently obtained favorable results for the firm’s clients. He has served as lead counsel in more than 20 IPR and PGR proceedings, representing clients both as petitioner and patent owner. Mr. Krieger has repeatedly beaten the odds: representing Patent Owners, 3 petitions were denied institution, and 3 IPRs resulted in favorable decisions after trial. All three cases resulted in the validation of all instituted claims—a result achieved in fewer than 5% of IPR proceedings.

Representing Petitioners, Mr. Krieger has been equally successful: In 2017, Mr. Krieger successfully represented Petitioner in two IPRs, resulting in the Patent Owner requesting adverse judgment. In 2018, Mr. Krieger successfully took three IPRs to trial on behalf of Petitioner. In 2019, he achieved another win as IPR petitioner, resulting in an early grant of a client’s motion to terminate the proceeding on terms highly favorable for the client. Overall, he has successfully represented patent owners in 6 proceedings and petitioners in 6 proceedings (several proceedings remain currently pending).

Mr. Krieger also actively prepares non-infringement and validity opinions including comprehensive freedom-to-operate (FTO) analyses in the chemical, polymer, medical device, and mechanical arts from both due diligence and litigation perspectives. Mr. Krieger also has been actively involved in numerous patent litigation matters and has participated in all phases of discovery, trial, and appeals. He is also experienced in Section 337 investigations before the U.S. International Trade Commission (ITC).

Mr. Krieger is also actively involved in numerous patent litigation matters and has participated in all phases of discovery, trial, and appeals. He is also experienced in Section 337 investigations before the US International Trade Commission (ITC).

Mr. Krieger lectures and publishes frequently on various intellectual property topics, including the America Invents Act, IPR and Post Grant Review (PGR) proceedings, best practices in drafting patent applications and the Defend Trade Secrets Act of 2016.

While attending law school, Mr. Krieger was a member of the Florida Law Review.

Mr. Krieger was recommended by Legal 500 US in 2018 and 2020 for Patent Prosecution. He was named a top patent practitioner in 2018, 2019 and 2020 by IAM Patent 1000 – The World's Leading Patent Practitioners.


Mr. Krieger leads a patent prosecution team for clients in the fields of industrial chemistry and chemical engineering, pharmaceuticals, agrochemicals, medical devices and analytical instruments.

He was lead counsel for patentee Celanese in five IPR petitions filed by competitor Daicel challenging the validity of Celanese patents related to industrial acetic acid production. The Patent Trial and Appeal Board initially ruled in favor of client Celanese, completely denying all five petitions, although requests for rehearing subsequently resulted in the institution of 3 of the 5 IPRs. In June of 2016, the PTAB issued final written decisions in the three IPRs, finding for patent owner Celanese and affirming all instituted claims as not unpatentable. PTAB Case Numbers IPR2014-01514, IPR2014-01515, IPR2015-000170, IPR2015-00171 and IPR2015-00173.

Mr. Krieger also served as lead counsel in five IPR proceedings in which client Celanese successfully challenged five patents owned by competitor Daicel Corporation. All five IPRs were instituted, with 2 being immediately terminated when Daicel filed requests for adverse judgement. Three of the IPRs proceeded to trial, where the PTAB found overwhelmingly in Celanese’s favor. PTAB Case Numbers IPR2017-00162, IPR2017-00163, IPR2017-00164, IPR2017-00165 and IPR2017-00166.

Kilpatrick Townsend also represented petitioner Celanese in an IPR petition challenging several claims of US Patent 9,776,941 to Daicel Corporation. Daicel made new arguments in its Preliminary Response concerning the scope of the challenged claims. In an unorthodox victory, Celanese moved to terminate the proceeding, without prejudice, in view of the new prosecution history created by the Preliminary Response. The Board granted the motion on April 12, 2019, resulting in significant savings to the client. PTAB Case Number IPR2019-00313.

As lead counsel, Mr. Krieger prevailed on behalf of Kilpatrick Townsend client Materion Corporation, securing denial of post-grant review (PGR) of US Pat. No. 9,989,684 relating to near infrared optical interference filters. The Patent Trial & Appeal Board concurred with Materion’s Preliminary Response, upholding the patent, which had been challenged for lack of written description, enablement, anticipation and obviousness. Viavi Solutions Inc. v. Materion Corp., PTAB Case Number PGR2019-00017.


University of Florida College of Law J.D. (1999)

College of William and Mary B.S. (1995) Chemistry


Colorado (2018)

District of Columbia (2002)

New York (2000)

Court Admissions

U.S. Court of Appeals for the Federal Circuit

U.S. District Court for the District of Columbia

U.S. District Court for the Eastern District of Virginia

U.S. Patent and Trademark Office (2001)

U.S. Supreme Court

Professional & Community Activities

American Bar Association, Member

Federal Circuit Bar Association, Member

American Intellectual Property Law Association, Member

Intellectual Property Owners Association, Member

American Chemical Society (ACS), Member; ACS Division of Chemical Education, Board of Trustees, Member (2020-2012)

ITC Trial Lawyers Association, Member

PTAB and TTAB Committee (Federal Circuit Bar Association), Member

PTAB Bar Association, Member

University of Denver Sturm College of Law, Adjunct Professor of Law, PTAB Practice (2021 Spring Semester)

Committee on Patents and Related Matters (ACS), Member


Latest Thinking

View more Insights
Insights Center
If you would like to receive related insights and information from Kilpatrick Townsend, please provide your contact details by filling out the form and clicking “Agree.” If you would like to access the PDF only, please click “Download Only.”