Jesus was a leader. He led not just by example, but through his deeds and teachings. While he did not govern, he certainly laid out rules for a just society and anticipated that these rules should be applied—and of course, if you have a society, there must be people who govern it. He called his disciples to go out and form a church. They were called to be leaders. They were called to organize and bring together the movement that became Christianity.
So I think Christ not only anticipated but appointed leaders who would have positions of authority. He gave authority to others, and gave clear directives on how people of authority (in the home or in public life) should behave. So I don't feel any contradiction between imitating Christ and exercising authority. The real issue is whether you handle that authority in a manner consistent with the gospels.
Editor's Note: Timothy Dalrymple primarily publishes interviews in his "Life in the Marketplace of Ideas" column. For more regular and original thoughts on faith, culture and politics, see his Philosophical Fragments blog.