Since Roland is tasked with following affairs related to Sadie, he meets her already knowing of her abilities and background. Due to this, Roland is quick to trust Sadie's judgement in Egypt. Roland is naturally flirtatious to a degree and frequently refers to Sadie as 'love', though that could just be his English nature toward women. Sadie also often reciprocates Roland's flirtatious advances, even on the friendship route. The two work well together and though Roland tries his best to keep Sadie out of his dangerous affairs, once she inevitably gets involved, he will do anything to protect her.
While Roland knows that much of what Sterling does is not directly his fault, Roland does not trust him and warns Sadie to stay away on multiple occasions.
In the main adventure in Australia, Sterling corners Roland. While Sterling greets Roland and says it's nice to meet him (which Roland responds with the feeling is not mutual), Sterling steals Roland's ID and Roland threatens to beat him to a pulp. In Roland's' Peru adventure, Sterling gets beat up by Viktor and Roland asks Sadie, 'Dare I hope he got shot? Wait. Some of the boys from your convoy told me about this, but I didn't... he was the gringo on the other side? The one that Viktor... Viktored? This is the best day I've had in a very long time, Sadie.'
Needless to say, Roland is not fond of Sterling, though Sterling seems indifferent to Roland.
The loss of Roland's ID may also be a contributing factor in one of Roland's endings, so if that turns out to be the case, Roland will be even more furious at Sterling.
Felix only meets Roland once, and that encounter only happens if you beat Sterling: The New Orleans Adventure before beating The Book from the Low Countries Adventure. Even so, in that brief encounter, Felix asks if Roland is okay after being kidnapped, so Felix holds no ill will toward him. Roland does not really mention Felix, but in that brief encounter, he was hospitable.
Nigel and Roland meet in Roland's main adventure when Roland goes to Nigel to translate some documents (actually to talk to Sadie). Nigel is very chipper about Roland and refers to him as a gentleman. Other than that, they do not meet again.
Anna meets Roland during The Anna Adventure. Here, Roland leads them through the pigeon gauntlet. Anna and Roland exchange pleasantries and are on good terms.
If dating Sadie, Roland goes with Sadie, Anna, and Evelyn to the movies.
As expected, Evelyn thinks that Roland is an attractive gentleman. Roland also likes Evelyn and thinks she is very lively, though he probably does not find her as attractive as she finds him. Their biggest interaction is during Easter on Roland's route.
While they never physically meet, Ruddy knows about Roland and has Sterling steal his passport. Due to this, neither likes the other.
Their relationship is never directly shown, though they do know each other. Zul knows Roland as his undercover name Rowan, and in Roland: The Australian Adventure, Roland 'warns' Zul about Owney Madden breaking into his office. Roland does not trust Zul.