MacMillan plans to step down on Nov. 11, according to Dan Egan, communications director for the Pennsylvania Office of Administration. He said MacMillan announced the move last Friday.
MacMillan, who declined to be interviewed, has clocked seven years in the role, entering office in March 2015. He came to the public sector after nearly 20 years at IBM, where he worked closely with numerous state governments.
His departure follows on the heels of that of another long-serving and high-level Pennsylvania IT officer, Erik Avakian, who stepped down Friday after 12.5 years as state CISO.
During his tenure with the state, MacMillan saw the Pennsylvania's 2017 transition to a shared service model that brought agencies' IT and human resources staff together in one centralized organization.
Egan said the state will announce an acting CIO to take over for MacMillan later this week.
