Having lived through the history of computers I believe the first portable computer was developed by a now defunked company known as Osborne. They created a portable computer called the Osborne Executave that resembled a sewing machine case. The credit for the first true laptop would go to Radio Shack with the TRS 100. The first modern type laptop, complete with hard drive, was introduced by Toshiba.
I may be wrong on the models but I think the companies are accurate. Someone please correct me if I am wrong.