Being a CIO is a tough job, but the job can be even tougher if you have a department manager who is just a little too aggressive toward you or the staff. Fortunately, there are some strategies you can use to cope with someone like that.
If the manager is being aggressive toward you, I recommend being polite but firm. Remember that you're the boss. Don't allow someone with an aggressive personality to pressure you into making uncomfortable decisions. When dealing with someone like this, you must be polite at all times. At the same time, your demeanor must reflect a will of iron. It's a tough balancing act, but it can be done.
Remaining polite, civil, and, most of all, calm is essential. You can't respond to aggression with aggression, or an already tense situation could quickly get out of hand. At the same time, you must remain firm in your dealings with the manager. Otherwise, you risk becoming a puppet.
That's not to say you should never accommodate your manager. Part of being polite is taking the time to listen to what the manager is saying. If the manager has a good idea, you should acknowledge and act on it. It's not only good for the company, but it also can help improve your standing with that person.
One of the things that I have discovered over the years is that, when people are super aggressive, it is often because they are overcompensating for insecurity. Maybe they feels inadequate, or perhaps they feel like they have something to prove. If you suspect that to be the case, then perhaps you can redirect the manager’s energy into something a bit more positive.
In IT, there always seem to be projects that nobody ever gets around to doing, because everybody is too busy. Maybe you can assign the problematic manager some sort of special project as a way of helping to build that person's confidence while getting the manager out of your hair for a bit. I'm not suggesting that you assign this manager busy work. Assign a real project that has real value to the organization. As I said before, you probably won't be able to resolve the situation unless you treat the manager with respect, and assigning busy work is not exactly respectful.
Another thing you might be able to do is to have an honest discussion with the person. Rather than asking why this person is always so aggressive, ask this person how things are going, and ask about long-term career goals. This type of discussion can build good will, because you are taking an interest in the person and looking out for that person's well-being. More importantly, you might even be able to get some clues as to the cause of the manager's behavior. Once you begin to understand why someone acts a certain way, it might become possible to make a few simple changes that improve the situation for everyone.
One last bit of advice that I would give you is not to tolerate abuse in any form. You simply cannot allow an aggressive manager to be verbally abusive toward you or toward the staff. If you allow the manager to verbally abuse you, then you risk emboldening that manager. If you allow the manager to berate the staff, then you risk employee turnover and even litigation.
Standing up to verbal abuse directed at you should be relatively easy. After all, you're the boss. You don't have to stand for it.
Unfortunately, if a manager is being verbally abusive toward the staff, you might not find out about it immediately. IT staff members tend not to view the CIO as approachable. As such, it may take a rather extraordinary event to cause someone to come to you about a problem with a manager. Staff members may instead choose to suffer in silence or look for employment elsewhere.
If you suspect that a manager might be mistreating the staff, then you should discuss your concerns with the HR department. Typically, large organizations have a protocol for dealing with this sort of situation. Trying to investigate and resolve the situation without involving the HR department might seem like the noble thing to do, but it could have legal repercussions.
Unfortunately, every situation is different, because every person is different. There is no sure-fire technique guaranteed to work in every situation. You might have to experiment with a variety of techniques before things start to get better. In any case, my own experience has been that being polite and treating the problem employee with respect will get you further than resorting to threats or belittlement.