How do U.S.-based search committees view job candidates whose Ph.D.s come from non-American institutions? I expect the Oxbridge set is fine, but is it something of a scarlet letter to have a doctorate from a foreign university, no matter its standing?
I feel like I have to front-load my answer to this question with caveats. So what I am about to tell you is true — but not always, not at all universities, not in all searches, not for all cases, etc.
Yes, a degree from the University of Oxford or Cambridge University is fine — in the same sense that doctorates from Harvard, Stanford, and so on are fine (assuming you are in a field that has a highly ranked Ph.D. program at those universities). When I say "fine," I mean they dominate in terms of cultural capital — with whatever implications that brings to a particular faculty search. Candidates with degrees from those places will have an absolute advantage in a search at a major college or university.
However, cultural capital of this kind can also work against you — for example, if the search is at a rural teaching-oriented public university, in an underfunded state system, in a region that has a hard time attracting and retaining faculty members. Folks on that sort of campus would most likely view any candidate with a degree from an elite university — British or American alike — as a minus. They would assume (probably correctly) that their position was being used, either as a steppingstone to a better job or as leverage in negotiations elsewhere. Places with limited budgets might also be reluctant to fly in someone from across the ocean. Finally, there may be pressure to hire regionally because the committee will see such candidates as more likely to understand "the culture" better.
Overall, R1 universities are more likely to be more open to applicants with foreign degrees beyond just Oxford and Cambridge, because research networks are inherently more international than pedagogical commitments. Faculty members at Penn, Chicago, or Berkeley, for example, will know plenty of researchers with degrees from, for example, the University of Tokyo, the Catholic University of Leuven, Humboldt University of Berlin, Tel Aviv University, or the University of Melbourne. These intellectual networks arise from research stints, conferences, funded workshops, joint grant applications, and such. Familiarity eases the chances of hiring Ph.D.s from those institutions.
Teaching-oriented campuses are going to be, on the whole, less interested in applicants with foreign degrees because there is an impression — a largely fair one — that overseas doctoral programs do not provide their graduates with much teaching experience.
Teaching assistantships are largely an American phenomenon — a product of a system in which a Ph.D. seeker is a student, on a fellowship, and some of the financial assistance a student receives is remuneration for labor provided as a graduate assistant. In many other countries, a Ph.D. seeker is a researcher — an employee, who may teach a bit but who is hired to perform research, usually on a grant brought in by his or her supervisor.
So even an elite liberal-arts college in a desirable city is likely to look at an applicant from outside the United States and wonder: How much teaching experience has this person had? Has the candidate spent any time in the classroom? And if so, has the candidate had American-style teaching experience — i.e., the lecture format?
You will notice that my examples above are from the so-called "developed countries" (a problematic term I’m using only for convenience here). That is because, by and large, in the symbolic economy of American higher education, global inequalities are reproduced much along the same lines as they are everywhere else. American search committees are likely to recognize/imagine parity of education with universities located in developed countries, less so with those located in developing countries. And, to go further, U.S. institutions will still view their counterparts in developed but non-Western nations — such as Japan and Singapore — as a rank down in status.
I am in no way defending that practice. It is not a good thing, or a fair thing. As a scholar of Japan I am infuriated when I see the superb institutions of that country disrespected. But I would be lying if I said that vestiges of colonial mentality do not linger in academia, and as a result, the West is imagined to have the monopoly on beacons-of-knowledge-caliber institutions. There are excellent Ph.D.-granting programs in Asia, Latin America, Africa, and Eastern Europe, but the recognition they enjoy is unfortunately often regionally limited.
Now I want to return to the caveats I mentioned. There are many exceptions to these trends, and people get all kinds of jobs with degrees from all kinds of universities. There may well be some circumstances in which an international degree can, in fact, be a boon. If a U.S. university is looking to hire an area-studies specialist, or a language instructor, someone with a degree from the area in question may have an edge. There can also be areas of thematic focus in which specific non-Western universities are dominant, and that dominance is understood by practitioners in the field at large.
So once again, I am not making a blanket claim that all non-Western Ph.D.s are marginalized in the same way on the U.S. faculty job market. I am making the rather obvious claim that relics of colonialist thought continue to shape the American academy. If you are concerned about your Ph.D. provenance, the best way to improve your job prospects at U.S. institutions is to publish in major American journals and attend major American conferences, thus rendering your scholarly record legible to American search committees.