We only hear about William Hastings from other people, since he died before the novel started. Hastings was Galt's boss at the Factory and one of the earliest people to join Galt's strike. From what we hear from Mrs. Hastings, William was an honest, hard-working man. What's really interesting about him, though, are the things that remain inferred and unspoken.
First off, we know Mr. Hastings must have been a pretty incredible guy for John Galt to work under him and invite him to join his strike in its early days. Second, Hastings didn't just jump at the opportunity to join the strike. We hear about his struggle from Mrs. Hastings, who apparently never learned anything about the strike or those involved, and from Midas Mulligan.
Mr. Hastings took a year before finally deciding to join the strike. Perhaps he was holding out so long because of his wife. It seems that those without any family connections had an easier time joining the strike than those with families to consider. This isn't true for everyone, of course, but it adds an interesting complication to Hastings's character. He's actually a lot like Dagny, in that it took him a very long time to decide to join the strike. He was sort of the first holdout.