Mr. O’Brien has served as Chief Executive Officer of Anterix since April 2018. He has also served as a member of Anterix's Board since April 2012, and as Vice Chairman from May 2014 to April 2018. In April 2018, Mr. O’Brien transitioned to serving as Anterix Chief Executive Officer. From January 2009 to present, Mr. O’Brien has served as an independent consultant to several wireless start-ups and until June 2017 served as a member of the board of directors of GTT Communications, Inc. (NYSE: GTT).

As a co-founder and chairman of Nextel, Mr. O’Brien led the creation of the first all-digital nationwide wireless network (the Nextel National Network) and brought push-to-talk (“PTT”) communication to the mass business and consumer market. After the merger of Nextel with Sprint Corporation in 2004, he was a co-founder of Cyren Call Communications Corporation, where he served until January 2009. Mr. O’Brien was recognized in 1987 as New Jersey Entrepreneur of the Year and was voted the RCR Person of the Year in 1993 and again in 2006. In 2005, he was inducted into the Washington, DC Business Hall of Fame, and in 2007 he was named a Fellow of the Radio Club of America and was named by Fierce Wireless as “one of the top U.S. wireless innovators of all time.”

In 2016, Mr. O’Brien was awarded the Armstrong Medal, the highest award of the Radio Club of America, for demonstrated excellence and lasting contributions to radio arts and sciences. Mr. O’Brien has also served on a number of boards of other public companies including Sprint and Williams Telecommunications. He also serves on the board of several private companies and charitable organizations. Mr. O’Brien is a graduate of Georgetown University and received his law degree from Northwestern University.