Aidan Rave joined the authority last Friday (16 June) after his appointment was ratified at a Full Council meeting the previous day.
Aidan joins following the departure of the council's current Chief Executive, Beverly Agass, who was in the post for eight years.
Councillor Matthew Lee, who was elected Leader of the District Council in May, said: "We thank Beverly for all of her hard work and commitment to our district over many years and wish her every success in her next role.
"Our challenge has been to find a new Chief Executive to help drive the Council forward positively in what I genuinely consider to be the start of a new era.
"Our district has many advantages and opportunities. We also face our fair share of challenges. We have therefore been looking for a candidate with drive, passion and ambition - and a track record of delivery.
"Following a rigorous interview process by a cross-party panel, Aidan was the stand-out candidate. His broad experience in the private and not-for-profit sectors will be invaluable, as will the fact that he has held elected office. We are excited to have him on board."
Commenting on his appointment, Aidan said: "This is an exciting time to join South Kesteven and I'm very much looking forward to working with members to realise some of the fantastic new plans we have in place for the District.
"Over the coming weeks I'll be getting out and about to find out how we can continue to improve services and achieve the best possible value for our residents."