The E28 has a self-supporting body that is welded to the body platform. The passenger cell is a safety passenger cell with deformation elements both in the front and rear of the vehicle. Unlike its E12 predecessor and E34 successor, the E28 has a rear-hinged bonnet. The boot has a volume of Template:Convert. Most models have a fuel tank capacity of Template:Convert,<ref name="BMW-E28-Betriebsanleitung" /> with some models having a smaller tank of Template:Convert. The kerb weight is Template:Convert.<ref>Template:Cite web</ref>

Cruise control, an on-board computer (to display trip information), and a "check control" panel (to alert the driver about fluid levels and lighting faults) were introduced to the 5 Series on the E28. The glazing is made of single-pane safety glass, the windscreen has laminated glass.<ref name="BMW-E28-Betriebsanleitung" /> As part of developing the air-conditioning system for the E28, several of the BMW engineers in charge of this program drove a previous generation E12 5 Series during the middle of summer in Texas. The E12 528i was painted black with a black interior, and driven Template:Convert in one day.<ref name=OBC86>Template:Citation</ref>

The styling was developed under BMW's chief designer Claus Luthe,<ref>Template:Cite book</ref> with development of the E28 beginning in 1975.<ref>Template:Cite web</ref> At the time that BMW was designing the E28, the company had only one computer, which was used for payroll management and spare parts logistics. Wolfgang Matschinsky and his team borrowed that computer to perform the calculations necessary to develop the new drivetrain and chassis. This was due to the fact that the addition of an ABS system necessitated a redesign from the previous model due to excessive vibrations under heavy braking.<ref>Template:Citation</ref>