She is charged with heading up InfoPrint – a joint venture between Ricoh and IBM – after the company's previous managing director moved to an assignment role within the business.
Lang has held positions in marketing and sales in the US and was most recently managing director of InfoPrint Nordics, Belgium and Netherlands.
Dermot O'Loughlin, general manager of InfoPrint Solutions Europe, Middle East and Africa (EMEA), said Lang would be taking the reigns with a team that has "incredible skills in emerging areas such as transpromo and multi-channel marketing".
He added: "Theresa has proven herself to be a stellar performer and we are thrilled she is now bringing her exceptional experience and leadership excellence to the UK and South Africa."
Lang said: "The role is a great opportunity to lead InfoPrint through the next stage in its evolution."
She added that she aimed to "take advantage of market position and technology leadership to the benefit of InfoPrint customers".
InfoPrint hoping new MD will boost market position
InfoPrint has appointed Theresa Lang as managing director of the UK, Nordics and South Africa, to lead the company "in the next stage in its evolution".