"I've been trying to build a relationship with my boss, but it isn't going so well. He seems to want me to be different than I am whereas I think we just have different personalities. In addition, he was recently turned down for a promotion. I feel that I am ready for more responsibility and I would like to put the concept of an expanded role on the table, but I wonder, if he can't negotiate his own promotion, how effective will he be in promoting me?"
What a challenge! It is complex because related issues are invovled. There are really two primary issues to address: The relationship with your boss and enlisting upward support of someone whose upward management skills you question. These issues require separate skills to address, and you will be more effective if you break them down and address them separately.
Addressing the relationship with your boss requires that you hear his feedback. You say that "He seems to want me to be different that I am." We suggest that it is not acceptable to allow that degree of vagueness to exist. It would be beneficial to know exactly where you stand in his eyes and how come, and how his perceptions relate to the ability of the department to reach critical goals. It would also be helpful for him to articulate what new behaviors in you would help accelerate progress toward critical goals. That way you are clear about his perception of your strengths and opportunities for development and your next steps are clear. This is not about changing your personality...it is about developing range and reaching goals.
Often when we have a perspective that is different from others, we can listen in a way that focuses on refuting their view. This can create an experience on the other side of "not feeling heard" which is quite damaging from a relationship perspective. First, focus on hearing your boss. Ask questions: "What do I do specifically that concerns you? In what way do you perceive that my behavior lowers the productivity of others?" Listening does not mean you agree, simply that you respect their perspective and the person offering it. Then, once your boss feels heard, advocate your perspective by linking your strengths to the department's success, as in "One thing I feel that I am strong in is that I offer a fresh perspective -- how can we make that strength work to the advantage of our group?"
In enlisting support from your boss for your expanded role proposal, express your thought process about being ready for expanded support and determine if he agrees. If not, get clear on what you need to demonstrate to earn his support. Put your concerns directly on the table in an effective way. For example, "do you perceive any limit to your ability to be an advocate for me?" Together, brainstorm ideas for how to address it..and whether near term steps are appropriate. For example, one approach would be to take a proposal to senior management together.