The FTSE 100-listed accounting software provider noted that Howell was most recently been group finance director of Close Brothers Group PLC (LON:CBG) for ten years, and prior to that, was CFO of the London Stock Exchange Group PLC (LON:LSE).
In addition, the group said Howell has been a non-executive director of Sage since 2013 and chairman of its Audit and Risk Committee.
Sage said it has initiated a process to appoint a new independent non-executive director and chairman of the Audit and Risk Committee.
Steve Hare, who took over as Sage’s chief executive officer at the start of November, said: "I am delighted that Jonathan has agreed to become CFO. He brings both considerable experience as a public company CFO as well as a strong understanding of the business.
“This, combined with our shared belief in the vision to become a great SaaS business for customers and colleagues alike makes him a great addition to the executive team."