Jim Bono shares a history with Troy Maxson that goes back to their time in prison together. As the men age, they take the same job and both keep to steady relationships. Bono admits to looking up to Troy and, for his part, Troy enjoys Bono's company and companionship.
From the first moments of the play, the relationship between the men is made clear.
Troy has been a role model for Bono, but Bono serves as a conscience for Troy.
Bono brings up Alberta in the first scene of the play, attempting to draw out Troy on the subject of his (potential) mistress. Troy refuses to admit to any wrong doing or even any special relationship with the woman, yet here Bono's role as Troy's conscience and moral counterpart is established.
As the play goes on, distinctions continue to be made that clarify the differences between the two men. Where Troy is a father treating his own sons just as he was treated when growing up (thereby repeating the past), Bono has avoided the path that his own father took.
Bono's father was a man with many women and many children. Bono, however, remains with Lucille faithfully and they have no children.
Bono's positive relationship with Lucille demonstrates that a man has the ability to change the direction of his life.
Unlike Troy, Bono seems to bear no bitterness for what happened in his past and he is content with the life he has established for himself. Troy is both bitter and ambitious, agitating for a new position at work.
These direct contrasts make Bono a foil for Troy, illuminating the strengths and weaknesses of Troy's character.