Grady is one of two gay men that Homer moves in with. The other is Julio, Grady's boyfriend.
The Simpsons finish a puzzle and have to find the last piece and Homer thinks that the piece is in the memory chest however finds a note saying that Marge wanted to dump him before he got married. This then upsets Homer and he finds an apartment in Springfield's gay district. He then meets his two roommates Grady and Julio who are two gay men who needed a third men in their apartment. Homer eventually finds out Marge really loves him after all and moves back into his house again, leaving Grady and Julio behind. In Three Gays of the Condo, Grady kisses Homer (implying he had feelings for him) but Homer later runs away saying "I'll only hurt you!".
Grady used to have a relationship with Julio, but Julio is seen married to Thad. Also, Julio cheats on either Grady or Thad with Duffman.
Grady is implied to have feelings for Homer after kissing him. However, Homer doesn't return those feelings and ends up running back to Marge.