Anonymous wrote:My peers at a top-ranked grad school for my field tended to have been very successful in college. Without good grades in college, I'm guessing you'd need to have pretty amazing recommendations and a very clear sense of purpose in order to get into a competitive graduate program.
And then there's getting a job at a highly ranked college. In my field, that's unattainable for all but a few, even among those with top grades in college and a Ph.D. from an excellent program.
Also, OP, the fact that you're asking not just about getting into grad school but employment afterwards at a top college suggests that you have a distorted perspective about this process. There are plenty of good jobs at places that are not highly ranked for example. But if somehow becoming a prof at a highly-ranked school is the main thing that matters for you, maybe grad school is not really for you. Focus on getting into a good grad school. Then find an adviser who can mentor you and show you the ropes. Then worry about where you get a job.
I say this because I didn't have great grades in undergrad but I got accepted into an interdisciplinary Social Science program - which was my first mistake, because most jobs are offered through standard fields and my interdisciplinary degree was a mystery to some places. But the big mistake I made was I chose an adviser who didn't know how to mentor me in the career norms I needed to address for the job market I was facing. I made a lot of mistakes professionally that I wouldn't have if I had chosen an adviser who had better knowledge about the job market. But hey that's all in the past.
All this is just to say that graduate school and the professionalization that occurs there is a long process. You need to embrace it to get a job in this job market. But if you don't want to start without a guarantee you'll get a top job, maybe this is not the field for you. Good luck with your decision!