- "I'm John Laurens in the place to be!"
- — John Laurens in Aaron Burr, Sir
Laurens meets Hamilton in "Aaron Burr, Sir", while in New York with his friends Hercules Mulligan and Marquis de Lafayette. The two bond almost instantly, and Hamilton states in "My Shot" that he "likes Laurens a lot." Laurens encourages his friends to take heart and have faith in the revolution ("The Story of Tonight"). In "Right Hand Man", Laurens, Hamilton, Lafayette, and Mulligan steal British cannons, and Hamilton becomes Washington's secretary. Laurens accompanies his regiment and Hamilton to a ball, where Hamilton meets his future wife Eliza ("A Winter's Ball"). Laurens is the best man at Hamilton's wedding, and teases him afterwards about finally settling down, a jibe at Hamilton's flirtatious nature. Laurens then asks Aaron Burr about his lover ("The Story of Tonight (Reprise)").
In "Stay Alive", Laurens becomes angry at the strong words from new general Charles Lee, and challenges him to a duel ("Ten Duel Commandments"). Hamilton is the second for the duel, at the close of which, Laurens shoots Lee in the side.
Laurens leaves for South Carolina, where he works to recruit an all-black military regiment. He is killed in a gunfight shortly after ("Tomorrow There'll Be More Of Us"). As he dies, he looks towards Alexander, who is on the other side of the stage, and their eyes meet.
As Alexander contemplates death in his duel against Aaron Burr ("The World Was Wide Enough"), he sees Laurens leading a chorus of soldiers in heaven.
Hamilton and Laurens are very close friends. After meeting in the second song, they are constantly seen together, and hug not infrequently. When Laurens is prepared to duel Charles Lee, he requests that Hamilton serve as his second, and then confesses that he considers Hamilton to be his closest friend.
In reality, Hamilton and Laurens exchanged a number of affectionate letters. In his, Hamilton stated multiple times that he loved Laurens. Hamilton never entirely recovered from his friend's death and, aside from Lafayette, never had such an intimate friendship again.
Marquis de Lafayette and Hercules Mulligan
Marquis de Lafayette and Hercules Mulligan are Laurens' two other friends in the musical. They both seem to show affection towards him, and are saddened upon the news of his death. While he is closest with Hamilton, Laurens is portrayed as knowing them first, and supports/is supported by the them throughout the show. The three all advocate for Alexander. During Laurens' Interlude in the musical, Mulligan and Lafayette are both on the upstage balcony reading letters of their own. When Eliza reads the section of the letter about Laurens dying, Lafayette drops to his knees and Mulligan takes out a flask and chugs it.