What sorts of credentials / experience would a junior person interested in a business development / strategy role at a startup need?

Passion for product: a BD guy closes deals, but he or she is not a salesman. Especially at startups, where both your brand and product is relatively unknown, a consultative approach, one that results in mutual benefits, stems from a deep understanding of and appreciation for the product. Operational excellence: to echo 's own sentiment, a BD person needs to know how to grow and scale a company. He or she is the company's voice to partners, and he is also the voice of the market for his own company; he or she needs to understand how to get internal stakeholders to buy in and execute on a acceptable time frames (understanding of sales cycles, contract negotiations, engineering sprints, and product launches and how they relate to one another is priceless here) Instinctive gut feeling: BD guys (at least the best ones that I've encountered) have prescience that I can only describe as powerful gut feelings. They can sniff out when a deal looks bad; they can anticipate when product will fail to deliver on a deadline, or deliver ahead of schedule; and they can predict where the market is going. That being said, a BD person's experience as a deal closer/product manager/operations guru and their own personal network can also help formulate their gut feelings. Addendum: In regards to the point about post-grad education, I don't think an MBA is necessarily a black mark on an entrepreneurial exec's resume. I think someone who combines pre-MBA start-up experience with an MBA actually is at an advantage because they can combine their understanding of small company dynamics (and the successes and failures that come with it) with their theoretical knowledge that comes with the two years of case studies. Food for thought :)

Startups (startup being a young smallish company will less than 50 employees) are not like big companies.  Rarely do you join a startup with a tightly defined role and just do that role.  Working at a startup is about coming up with efficient ways to solve problems with limited resources (e.g. time, capital, other smart people, brand name, etc).  Whereas big companies might actually care if you have an MBA/CFA/CPA/etc or spent two years at an investment bank, startups need passionate people that can help them solve problems, be them technical, marketing, business development, or any other type of problem.  At a startup, many times you sacrifice a brand name (e.g. GE, Microsoft, Google, Goldman Sachs), a market rate salary, and a well-defined box-of-a-role, for uncertainty and upside.  If I were a CEO, I'd care a lot more that you are passionate about the problem I'm trying to solve, familiar/use my product, have a perspective on the competitive landscape and how we can improve our position, are willing to do whatever it takes (e.g. development, sales, marketing, take out the trash) to help us be successful, how your background/set of experiences is relevant to my business (rather than just looks good on a resume) than I would about whether you have an MBA or worked in banking. 

Bring 1) answers to problems the startup is facing and 2) some level of operational experience that proves that you can execute on the answers you've provided. Unfortunately all the credentials you listed (MBA, Banking, Consulting) proves neither of the two.  This coming from someone who had all three of the credentials, was completely useless at his first startup (VP of BD), and had to work 7 years at both startups and at a 'big' tech company (eBay) in operational roles to start being useful to a funded/fast growth startup right back into the role I had 7 years prior (VP of BD).