I applied through a staffing agency. The overall process took about 3 weeks.
The first step was to interview with their in-house recruiter. It was in person, maybe 25 minutes long, and mostly talking about my resume.
The second step took place maybe 1-2 weeks later. It was about 2.5 hours and I interviewed one on one with four people back to back, including two management staff in the department I was applying for, one HR person, and the AA who was leavinLotg the position they were hiring for (due to moving within the firm internally). Everyone was very friendly. I received an interview schedule beforehand, and everything ran on time and according to the schedule. They asked a lot of questions to figure out if I was a good culture fit, as well as about my past experience and career trajectory. I definitely came away from the meetings thinking that they wanted to hire someone to work for the firm for a long time, not just a random AA to answer phones for a year.
The third step took place the following week. It was about 2 hours long and I interviewed one on one with three people back to back, including the department head, a senior person in the department, and a more senior executive. This round was more challenging, although they asked the same types of questions that were in theory about my past experience, but more about what kind of employee I was and how I'd fit in at the firm. Again, I received an interview schedule beforehand and everything ran exactly on time.
I received an offer the following day, and was told I had to decide within one day.