Cllr Johnson, the Conservative Member for Stamford St George's, was Vice-Chairman last year.
She paid tribute to her predecessor as Chairman and said: "Cllr Helen Crawford has been a fantastic role model and has represented this Council better than anyone I have ever known to do it.
"I thoroughly enjoy my role as a councillor, meeting and helping new people and learning about my local area so I am delighted to be chairing this year."
Cllr Johnson was elected as a District councillor in 2019, and has been a Stamford Town Councillor for a number of years. She was Mayor of Stamford in 2021/22.
Born near Doncaster, Cllr Johnson has lived in Stamford for the past 43 years. Before settling in the area she moved frequently while her husband, Kenneth, served in the Royal Air Force.
The couple have two sons, Tony and Ian, who both work in engineering, four grandchildren and three great-grandchildren.
Cllr Johnson worked at a local supermarket for over two decades where she became a supervisor, and later a manager.
As she stepped down as Chairman, Cllr Crawford said: "What a year to be a Chairman, with so many national comings together. The Queen's Jubilee, the sad passing of the Queen, the proclamation of King Charles and the Coronation of King Charles III.
"It has been an honour and a privilege to meet so many people who support and help so many and to attend so many events and functions."
She thanked all those who supported her during her year in office.
Cllr Paul Fellows, Independent Member for Bourne Austerby, was elected Vice-Chairman for 2023/24.