Gunther brought his family from the old country when his son, Mortimer, was just a lad. Having amassed quite a fortune, he is founding father of the neighborhood.
You can tell just by looking at him that Gunther Goth comes from old money. But he doesn't seem arrogant or greedy, just comfortable with the fact that he has been rich all his life.
In The Sims 2, Gunther is one of the pre-created, yet unplayable Sims featured as ancestors of playable, pre-created Sims. Though deceased when the game begins, the player can see him in the relationship tree of playable Sim Mortimer Goth, who is his son, as well as those of his grandchildren, Cassandra Goth and Alexander Goth.
Gunther lives with his family, Cornelia and Mortimer Goth, in a large house located by the graveyard. There is no specific mention of him being the founding father of the neighborhood, but he has many good friends and on the Goth Manor is described as the first house built in town. Instead of the Goths being 'heads' of the town, the Landgraab and Alto families seem to have more control over the town, though Goths appear to have been influential in creating the town's ethics.
Gunther has long brown hair, and wears a flamboyant top hat. He is a CEO in the Business career track, and although married to Cornelia, he does not have an outstanding relationship with her (they do not want to WooHoo with each other and they must increase their relationship level to accept WooHoo with each other). This however contradicts Mortimer's bio, which says: "The Goths' strong marriage has produced a healthy boy named Mortimer." Also, it appears that he has never even met Cornelia's sister Agnes Crumplebottom, even though Agnes is Cornelia's best friend. He likes to swing and read.
Life leading up to The Sims
Gunther and his wife Cornelia Goth, along with their two cats, Hecuba and Menelaus, first appeared in The Sims: Unleashed. He is the founding father of the neighborhood, which made him very rich indeed. His hair is grey or white around the edges, and black on top, which is a bit odd since his hair in The Sims 3 is brown. He wears a phantom-like dark gray tux with tails and a light grey bow tie. He is a Dean in the Education career track, in contrast to his CEO job in The Sims 3. The reason for this is left to the imaginations of individual players. His relationship with his wife appears to have improved greatly and scores a 98/100.
When first played in Neighborhood 1, he will have no relationships with Mortimer, Bella, and Cassandra.
Life leading up to The Sims 2
In The Sims 2, Gunther and Cornelia had lost their lives in two separate fires. He died when his second grandchild, Alexander, was born. His wife died a bit later, just before their son, Mortimer, retired. He is buried in the new Goth home with Cornelia, his parents, father in-law and sister in-law. His hairline has receded since The Sims, and his hair has gone completely grey. He wears a black suit with a striped blue tie. According to SimPE, his hair was black before it turned grey, implying that he dyed his hair brown in The Sims 3.
In The SimsUnleashed, Gunther lived with Cornelia and their cats Hecuba and Menelaus in a large mansion at 77 Maple Street of Old Town, a little further from Sim Lane. The home has a small graveyard (like all Goth homes) but there are no ghosts so it is not known who is buried there. Perhaps, Gunther died in a fire in the mansion, then Cornelia died in the Goth home, which then was re-constructed into a new and improved house for Mortimer, Cassandra and Alexander Goth in The Sims 2. In The Sims 3 Gunther, his wife Cornelia and son Mortimer live in a big house by the cemetery.
In The Sims his hair is black with gray at the sides, but it is auburn in The Sims 3.
Gunther's career track being changed from Education in The Sims to Business in The Sims 3 may be because the Education track is not present in The Sims 3 base game.
Interestingly, in the The Sims, a Minister of Education will eventually switch careers and become a President in the Business track. Gunther's switch from Business to Education mirrors that.
In The Sims 2, Gunther uses a character portrait pose that was discontinued for his gender during development.
His lifetime wish in The Sims 3 is to master 3 skills. He appears to be close to achieving that wish in The Sims, as he almost has 3 skill points in Charisma, Creativity, and Logic.
In The Sims: Unleashed, Gunther is referred to as Gunther Goth, Sr even though there is no Gunther Goth, Jr. This was to differentiate Gunther's household and Mortimer's.