I enlisted in the Air Force and then went from active duty into AFROTC at San Diego State University. ROTC teaches cadets leadership principles and military skills. ROTC taught me quite a bit and those lessons have served me well throughout my career in IT.
In basic I learned how to march, dress, and do all of life's activities in a hurry while being yelled at - and to always take my hat off when coming inside. I also learned responsibilities. I can't think of any other place where a 19 year old is given more responsibility than I had at the time. I showed my superiors I was trustworthy and they put their trust in me. Lesson number one - earn the trust of your team.
After active duty I enrolled in Air Force ROTC at San Diego State University. The ROTC mission is to produce leaders for the Air Force and build better citizens for America. We did a lot of marching and work outs, and learned what "Duty, Honor, Country" meant to us, but what really struck me was the third year. An entire year focused on leadership. In particular the works by Huntingtion and Janowitz. Their lessons apply as well to anyone calling themselves a professional.
To be a professional requires expertise. This means an education and training above and beyond the general public in whatever area you want to enter. In particular, expertise that your client does not have but is counting on you to provide. Always treat your customer with respect and keep up on whatever certifications are required for your role. As a manager keep your team current on their training and professional development.
Responsibility in the military means "Duty, Honor, Country." In civilian terms it means being motivated and passionate about what is is that you do. When your pager goes off at three in the morning you answer it because it's who you are.
Finally, corporateness (for the civilian) means that there is a professional body that you are active in that advances your profession and has a code of ethics that you adhere to. I'm happy to say I'm heading to an IEEE symposium tomorrow!
If you find yourself leading a surly team of BOFHs that punch the clock and frequently miss their oncall page you may need to instill some professional pride.