Mortimer and Bella had previously appeared, in slightly different versions from the final release, in promotional materials for the game, including renders and the The Sims 4: Create A Sim Official Gameplay trailer.
He works as a B- Movie Star in the Entertainment Career Track.
Mortimer Goth was born outside of Sim City, in the Old Country, which could refer to a place such as the United Kingdom, or an unknown rural area, or could be a way of saying "someplace else".
His father moved the family to Sim City when Mortimer was young.
He rose through the ranks of his career from a Test Subject to a Mad Scientist, and became quite wealthy along the way.
His parents, Gunther and Cornelia, both perished in two different fires.
Because Mortimer had reached level 6 of the Science career, prior to his retirement, he has a Science career reward available for him to purchase.