Leland worked alongside Hester for years as her research assistant, becoming very close to her. Later, Leland quit working with psychiatry and moved to Paris. After some time in the Paris art world, Leland earned a seat on the board of the Paris Museum of Modern Art. In "Fathers and Sons", Leland came to Seattle to visit Frasier, Niles and Martin. During his visit, he turned out to be extremely similar to Frasier and Niles in taste in art, clothing, culture and even had some of the same mannerisms and allergies, resemblances which Roz pointed out.
Because of this, Martin began wondering if Leland was their father, as Hester had cheated on him once before with someone else, and she and Leland had been very close. On Leland's last day with the Cranes, just before he was going to leave, Martin finally asked him just how close he and Hester had been, subtly inquiring if their relationship was anything but platonic. Leland explained that he is gay and couldn't therefore have slept with Hester, though he did confide his orientation to her. This was in itself a sign of their closeness, as at the time careers and lives could still easily be ruined by such a revelation. Martin and Leland then parted on friendly terms, expressing their mutual fondness for Hester, and Martin telling Leland that Hester had loved him too.