Grad student at a research university here. I'll discuss generally what faculty here do but I can fill in on the grad student experience if you like as well.

At a large research university (in comparison with, say, a small liberal arts school), faculty are mostly focused on producing valuable research. For historians this means articles and, as often as possible, books. These projects are focused on using primary source research to engage in the ongoing conversation between historians of a given topic/field across multiple institutions and nations.

The process of research has a lot of facets. Historians need to compile sources for their projects, which sometimes can be brought to the university through library exchange systems. Other times the historian needs to visit various archives applicable to the project. These research trips can be as short as a few days or as long as a semester or year (usually called a sabbatical). Often the professor needs to secure some external funding to finance these trips, meaning grant and fellowship applications. Once the research materials are compiled there's the matter of sifting through them, analyzing, and producing scholarship based on their findings.

This scholarship is useless if it isn't prepared for broader consumption in some way, and historians engage in this process in three primary ways. The first is academic conferences, which are gatherings sponsored by various organizations of historians, usually centered on a specific theme or field (like the Society of Civil War Historians, for example). Here historians organize sessions where they present smaller versions of their research to one another in a more conversational setting. More formal presentations of scholarship come through publications. Historians can seek to get articles (about 30 page research pieces) published in any number of journals. This process can take a long time from initial submission to final publication, involving a lengthy review and editing process which can require extensive additional research and reforming of articles. Finally, historians at research institutions are expected to regularly work on longer book projects. Think articles on a grander scale.

In a given semester a historian at a research institution will be working on some combination of the above. A new assistant professor will be under immense pressure to make good progress on a book (usually their first), along with a regular rotation of conferences (both presenting and just attending) and grant/fellowship applications.

Notice how I haven't mentioned teaching yet. It's there, but can often be of secondary importance to historians (and most faculty regardless of field) at large research institutions like the Big Ten. But teaching expectations are still there. A 2/2 load is fairly common, which means a professor is expected to teach two courses a semester or equivalent (unless they are on sabbatical). This involves preparing course lessons and assignments, grading, holding office hours, and the administrative logistics. A large research institution is more likely to have teaching assistants of some kind who can provide some assistance here. There are likely also graduate students that a professor is mentoring, which can be a time-consuming or laid-back process depending on the student and professor, but will certainly involve some measure of evaluation, guidance on progress toward a disseration/thesis, etc.

On top of this all will be various administration-related responsibilities within the department, all of which depends on the organization of that individual department (this varies widely). It could mean service on various administrative committees like overseeing changes to the curriculum, handling department funds, etc. Some professors will be tasked with various supplemental administrative roles, such as Director of Undergraduate Studies, or heading up the departments Honors program for undergraduates, etc.

In sum, if you're at a large research school, you can bet that your history professors do a hell of a lot more than show up a couple hours a week and give lectures to undergraduates. That's actually a pretty small part of their job. Instead their job is usually a handling a large number of individually small projects at once. Preparing a conference paper here, finishing a grant application there, handling Grad Student X's thesis defense, running a couple courses for the semester, preparing a research trip next month, etc. Some of these projects get fairly large, especially books. But the projects themselves can often be shifting.

Hope this helps.

if by historian you mean a college professor, a regular tenure-track or tenured professor in a history department at a research I university-what most people think of-then everyday duties revolve around three big areas: 1) teaching (takes up bulk of the time); 2) research; and 3) service. professors generally make up their own schedules but certain days are teaching days, other days are teaching/committee days, weekends and breaks probably for research and writing.

I interned at my local university (that I'm enrolled to) this past summer under a research program. It was only for about 2 months but the professor I worked with told me this is how most of the researching is done.

You first need a topic, a problem, a question to find an answer for. You spend hours at a library looking for books to give you context and historiography of the problem. Usually once you have a general context, it's time to move on to primary source research. This may take days or weeks to do. Primary sources can range from books to internet archives.

It really depends on the end goal. The goal for my seminar was to present the research at the end of the seminar on a poster, it didn't have to be definite but it had to look like it would go somewhere. Hope this helps.

History teacher here. Typically plan lessons and impart historical knowledge on a daily basis. Oh, and if there's time, I do some research.