Communications with a stakeholder is difficult because he is overbusy. The stakeholder is higher up in the organization and is doing things without informing the PM.
Left out in Reading, PA
Dear Left out,
It looks like you have two problems, the second one being more serious.
First of all you have a high level stakeholder with whom it is difficult to communicate because he is super busy. That is pretty typical and you just need to get on his calendar on a regular basis. Find out how he prefers to be communicated to and use voicemail, e-mail, phone calls, Webinars, face-to-face visits or whatever works best. Get to know his Administrative Assistant and get on his calendar. Remember: 90% of a Project Manager's job is communication. so do your job here.
Your bigger problem is that he does things without informing you. I can read between the lines and suppose that the things he is doing is hindering your progress on the project. And, since you mention the first problem you believe the two are related. The stakeholder is doing things that affect your project that he wouldn't do if you were able to communicate to him properly.
OK, so you now know some ways to improve your communication with the stakeholder, what can you do to ensure that he stops interfering?
I've found that project stakeholders respond well to impacts. Show them the impact their decisions and actions are having on the project constraints. Are they adding to the scope or risk? Are they increasing the schedule? Are they removing resources or reducing quality? Are they adding cost? It's possible he could be doing the opposite of all or any of these.
Show him, in graphical terms, what is happening to the project because of their actions. Emphasize that you, as the Project Manager, are the focus of the project and only you know the overall impact these actions have. Ask that he run these decisions or actions through you so that you can analyze the impact before they become reality.
This is what I mean by graphical. Make it clear which alternative he should take by using scaled arrows and few words:
Send me your questions at email@example.com