He is married to self-professed gold digger Bambi Landgraab, and is a gene therapist. This implies that, if he is the same person as Malcolm Landgraab from the PC game, he followed his father into medicine instead of his mother into business.
Unlike the Malcolm Landgraab from the PC, Xbox 360, and PlayStation 3 versions of The Sims 3, he has dark skin, black hair, and brown eyes. In addition, the two have no traits in common. While he is younger than the Malcolm in the Xbox 360 and PlayStation 3, it appears that they are either not the same person or that the The Sims 3 for Nintendo DS is in a completely different continuity.
He and Bambi start off with §70,315, which is slightly more than the amount Alex Goth starts off with.
It is possible that he could be the son of Malcolm Landgraab IV, making him "Malcolm Landgraab V", but this link has not been confirmed.