Account Managers are hired both internally and from outside. Typically the job the posted on websites and on the Co website, recruiters screen the resumes and invite suitable candidates for an interview first with HR then with the hiring managers ( Ad Directors,VP, EVP) If you are hired from within you are interviewed directly by the Ad Director and the VP first.

I received an email from a recruiter to set up a phone screening 2 months after I applied for a job and had forgotten I applied. They sent a link to select some time on their calendar. I replied confirming that I picked a time and asked for confirmation on which position it was, to which I never received a reply. (Thankfully I had only applied for one position so I was able to assume correctly). A link was sent for a video interview with a dial in number but it was only a phone interview, no video. Interview seemed to go very well and connected with the recruiter minus that the salary they were offering was a bit lower than what I asked for. Recruiter asked me to think about the salary and confirm if it would be okay before moving forward to an in person interview. After some thinking I confirmed it was doable and sent him an email confirming that I'd like to move forward in the process while thanking them for their time. Unfortunately that was the last I heard from the recruiter and about a week later I got a generic rejection email. But with a lower than average salary in NY for the experience they're looking for an no moving package, this probably wasn't the right position anyways.