Does your undergraduate really not matter if you want to go to HBS?

I’ve been asking around about advice on what I should do during my undergrad if I hope to one day go to HBS but most replies have just been telling me that it doesn’t matter and that they will only care about what you do in the years after college. How true is this?

I’m majoring in a STEM and I go to a good undergraduate school but I want to know if there is anything else I should do now while I am still in school. Should I take business course? Should I minor in something?

Harvard is hard to get into so I want to get ready early.

Get great grades, join or start several organizations of interest and become a leader, start your own business doing something you love and/or intern/work for the best companies you can find during your summers or off terms. Find a successful business mentor from your college who, ideally, went to HBS. Do some community service regularly (perhaps start an entrepreneurial camp for underprivileged kids, join Big Brothers/Big Sisters, help with the Boys and Girls Club, tutor someone in need, or feed the homeless or take them books–whatever makes you happy).

Also, get a very high GMAT score.

Network, so you can line up a good job after graduating and work at least a couple of years with your HBS graduate supervisor making tons of money so he or she can give you glowing LORs.