The vice-president, who replaces the outgoing Peter Bretherton, was sworn in at the LTA's annual general meeting at the Roehampton National Tennis Centre in London yesterday.
"Cathie's qualities, know-how and experience make her eminently qualified for this role," said Bretherton. "With her at the helm for the next three years, British tennis is in good hands."
Sabin herself pledged to keep pushing to improve participation levels in the sport across all levels.
Addressing the annual meeting, she said: "I am really looking forward to working with you all and coming out around the regions to visit your teams. Thank you so much, and I would also like to thank Peter for his support and guidance over the last three years."
Stepping down after his three-year term of office, Bretherton also insisted the LTA is indebted to its former chief executive Roger Draper who was criticised when his £640,000 salary was revealed in the 2012 annual financial report and whose departure from office has not been mourned by many.
He left his role in September and will be replaced by head of Tennis Canada, Michael Downey in January. "During his watch, the organisation was transformed," said Bretherton. "He introduced the British tennis membership scheme, and was instrumental in the professionalisation of the talent identification scheme. British tennis owes Roger an enormous debt of gratitude."