Lewis is the mayor of Pelican Town, and In parallel with his work as mayor, he is also involved in the Stardew Valley Agricultural Fund.
As nobody has challenged Lewis for his title of mayor in the twenty years he has held the position, we can assume he has a good relationship with everyone living in Pelican Town. He was apparently good friends with the farmer's grandfather.
He has never been married and has no family; all he lives for is being mayor. He sometimes questions if it was worth it.
That being said, Lewis is known to have some sort of relations with Marnie, as the shorts he lost and brown suspenders are found in her bedroom.
Furthermore, a note can be found in his bedroom in the lower left on a shelf under a coffee mug, believed to be from Marnie. The note is signed "-M".

Lewis' favorite gifts are:
Autumn's Bounty, Glazed Yams, Green Tea, Hot Peppers and Vegetable Medley.