Deirdre describes Wallace as a "sort of a cross between an adorable uncle and a completely creepy school teacher."
Through Deirdre's blog posts, we have learned that Wallace is at least 80 years old as he worked with Deirdre's grandfather Warner Green. He previously worked for Grey Ackerly's attorney and was around during the early days of Ackerly Green Publishing. Wallace later became the Green family's attorney and helped with Sullivan Green's transition into taking control of A&L Printing. Wallace continued to assist Green with the publishing company before it burned down in 1979. Shortly after this occurrence, Sullivan Green disappeared and Wallace kept track of Green's bank account, topping it up when it ran low. Wallace heard nothing from Green for nearly a decade, until he was contacted by a group who were seeking Mr. Green. Working with the group, Wallace found Green and acted as his ward and friend until Green's death in 2016. Upon Green's death, Wallace was given a letter that the police had found on Sullivan Green's body. The letter explained the existence of Green's daughter, Deirdre, and lead Wallace to Green's abandoned brownstone. 
Wallace currently acts as Deirdre Green's lawyer and advises her on things, including the re-opening of Ackerly Green Publishing.