From 2003 through 2007 he served as the head of Massachusetts Bay Transportation Authority Police, leaving the job in September 2007 to take the full-time Adjutant General's position in the state's National Guard.

He took over the position on September 21, 2007, but was officially sworn into the job on October 26, 2007, by Governor Patrick at a ceremony conducted at the Massachusetts State House.

During his tenure as TAG he received a state (but not federal) promotion to major general[2] and Massachusetts has been twice recognized for excellence in Diversity and Equal Opportunity.

[3] On March 29, 2012, he was suspended with pay from the National Guard by Governor Patrick pending the outcome of an investigation into an allegation that he raped a servicewoman in his unit in 1984 during training at Eglin Air Force Base in Florida.

This is in contrast to a statement by Murray who claims Carter was questioned during the investigation about the incident and stated "Well I hope this doesn't impact me some time in my future.

[12] On September 19, 2012, BG Carter agreed to retire from the Massachusetts National Guard after a report from military investigators that "found probable cause that he indecently assaulted a subordinate while the two were on a training exercise in Florida in 1984".

[13] Investigators stated that they did not find evidence to substantiate a charge of rape, but concluded that "he probably touched her inappropriately, engaged in conduct unbecoming of an officer, and later made false claims about the incident".