Gregory H. Lantier

Gregory H. Lantier is a seasoned patent litigator and appellate advocate with a practice focused on complex intellectual property disputes, including patent, copyright, and trade secret infringement, as well as IP ownership and licensing matters. He represents clients across a broad spectrum of industries such as computer software, medical devices, financial services, telecommunications, defense, semiconductors, pharmaceuticals, and biotechnology.

Lantier primarily defends operating companies, having a strong track record of securing favorable outcomes against patent assertions. His experience includes numerous Federal Circuit victories, notably invalidating patents for clients like Universal Wilde Inc. and Erie Indemnity Company. While often representing defendants (2 out of 3 tracked appearances), he also has experience on the plaintiff's side, as seen in a multi-year litigation for Amdocs Ltd. against Openet Telecom Inc. that concluded with a mid-trial licensing agreement.

He recently joined Sidley Austin LLP as an Intellectual Property partner in January 2026, transitioning from WilmerHale (and its predecessor Hale and Dorr), where he previously co-chaired the Post-Grant Patent Proceedings Group. His notable engagements include representing Viant Technology LLC as a defendant in Intent IQ LLC v. Viant Technology LLC, a patent infringement case related to advertising platform products, which has seen related inter partes review (IPR) proceedings filed at the PTAB. He also defended Neurent Medical Ltd. in Aerin Medical Inc. v. Neurent Medical Ltd. et al., involving medical device technology for nasal treatments, a case also linked to ongoing IPRs.

Lantier possesses a nationally recognized post-grant proceedings practice before the USPTO's Patent Trial and Appeal Board (PTAB), where he has represented both petitioners and patent owners in dozens of IPR proceedings. He earned his law degree from Harvard Law School and clerked for Chief U.S. District Judge Rebecca Beach Smith of the Eastern District of Virginia. He is admitted to practice in the District of Columbia and New York, and before several federal courts, including the U.S. Court of Appeals for the Federal Circuit.