Calvin is a brilliant researcher at the Hastings Research Institute and is widely thought to be on a trajectory to winning a Nobel Prize in Chemistry. He has had his pick of academic institutions throughout his life, with the notable exception of Harvard, which rejected him as an undergrad and which he’s subsequently always detested. He chose to come to Commons—where the weather is largely mild and sunny—because he hates the rain and loves to row. This reasoning infuriates his colleagues, as do many other aspects of his personality. He’s famous for forming and holding onto nasty grudges. 

Although he’s academically superb, Calvin struggles with social interactions. He tends to self-isolate and be very awkward, which prevents him from having any romantic partners until well into his thirties. This all changes when he meets Elizabeth Zott, whom he gets on with famously. Despite a less-than-ideal first encounter where Calvin mistakes Elizabeth for a lab assistant, and a second where his sensitive nose causes him to vomit all over her, the two quickly fall in love. Their relationship, although it’s monogamous and loving, defies the social expectations of the 1960s. Elizabeth prioritizes her scientific work over everything else and has no interest in getting married or having children. Calvin wants to marry her and hopes to gradually persuade her to change her mind about both. He’s almost obsessively in love with her, to the point where he thinks about losing her constantly. 

This is partially due to Calvin’s difficult and abusive childhood. He was raised in an orphanage and led to believe his parents had abandoned him. It’s also implied that he was molested by the Catholic priests who ran the boys’ home, a fact that he only lets slip to Elizabeth. He wants a family, but loves Elizabeth so much that he’s willing to potentially give it up for her if he can’t bring her around. When he dies suddenly, the fact that they aren’t married makes things significantly more complicated for her. Calvin’s estate must go to his closest relative, so Elizabeth is left out in the cold.  

At the beginning of Lessons in Chemistry, Calvin’s relationship with his boss Robert Donatti is already strained. It becomes exponentially more so when Elizabeth's scientific contributions at Hastings go unrecognized. Donatti simply doesn’t believe Elizabeth can do the work she is already doing. He’s dedicated to preserving the traditionally male halls of power in the sciences. Calvin, on the other hand, readily acknowledges Elizabeth's talent and actively chooses her as an intellectual partner. He also fights for her to receive the recognition she deserves, regularly advocating for her achievements and challenging the gender-based prejudice and violence that Donatti perpetuates. Because of this, and because of his awkwardness, Calvin is not a popular figure with the other scientists at Hastings. However, he’s the subject of a lot of discussion by the institute’s women, as he’s famous and rumored to be wealthy. When he and Elizabeth begin their relationship, people are publicly disapproving and privately jealous. After he dies, they take out all their resentment on a grieving and pregnant Elizabeth.