The phrase 'understood the role of' is correct and usable in written English.
For example, "The resource manager quickly understood the role of each team member in the project."
Others concluded that neither Tillerson nor Trump understood the role of diplomacy in American foreign policy.
He deeply understood the role of the citizen in city affairs and was committed to improving and unifying our community.
She deeply understood the role of the citizen in city affairs and was committed to improving and unifying her community.
John Russo, a Greenburgh real estate broker, said that while he understood the role of the state in such problems, he also believed that counties need to strive for efficiency.
Abbas understood the role of the visual arts as a tool of power; he understood how Iran could exert lasting influence from Istanbul to Delhi with an "empire of the mind", as the historian Michael Axworthy has described it.
I don't know that Ed Miliband understood the role of business in the economy in terms of the power for good: it just isn't a place that he's been to in his life.
