Find somebody who has had experience managing a remote team, preferably somebody who understands the cultural differences between your team and the remote team. This requirement stands even if you plan to outsource onshore!
Besides the appropriate technical qualifications, the ideal engagement manager must have very, very good people management skills and be courageous. That’s because he/she is going to represent the remote team to the local team and vice versa. On occasion he/she will have to push (or push back on) one team or another. This is difficult enough to do face to face, and it is even more so to do over the telephone (i.e., this is one of the reasons that regular travel to the remote site is mandatory for the Engagement Manager, see below).
The Manager has to be very proactive and not somebody who simply asks for status and takes it at face value. It’s not necessarily a question of whether or not people are telling the truth; rather, it is matter of getting to the bottom of things. Something as simple as “yes” or “done” mean different things in different parts of the world; their meaning may vary depending on the question!
Most of all, the Engagement Manager has to be located in the US, at the same location as your core development team. Trying to do this with the Manager at yet a third location adds exponentially to miscommunications and ultimately to productivity loss. There are some people who can manage this and I am fortunate to know one of them, but they are beyond rare.
The Engagement Manager and the Tech Leads must be willing and able to work an appropriate shift that overlaps sufficiently with the US-based team and the remote team. For an offshore team in India, this may mean a 2:00-10:00pm schedule to overlap at least for three hours with each team. For a nearshore team in Mexico, with only two hours off the US schedule, their schedule can remain the same as the rest of the team since there’s plenty of opportunity to keep in sync with the remote team throughout the day.