Katie Irani was born on 27 February 1920 in her mother's family home in Ahmednagar. Her parents were Rusi Jehangir Irani, known as Rusi Pop, and Khorshed Banoo Irani, and her elder sister was Dr. Goher Irani; her other siblings included Roshan, Jal and Aspi. The family lived in Quetta, and when Meher Baba stayed in Rusi's home there in 1923, Goher was seven and Katie three. Baba played with all of Rusi's children but was most attentive to the two sisters, and little Katie told her father that Baba was such a fine gentleman that he should not be allowed to leave.
Baba stayed with the family in Quetta again in 1929 and in 1931. In 1931, when Katie was eleven, he teased her, dictated her school essay and taught her never to refuse what he gave. Katie was sent as a child to live with her mother's relatives at Khushru Quarters in Ahmednagar, and the family later settled there; by 1938 she was coming to Meherabad with Goher during school holidays.
In December 1938, at eighteen, Katie was allowed to join Baba and the women mandali in Hyderabad at the start of the Blue Bus tours, and she remained in the women's ashram for more than a decade. She cooked for the women, with Manu Jessawala at first, and acted in and helped Mani with the humorous skits staged for Baba, once playing Mussolini. She lived with the women at the Links in Bangalore and in their secluded compound on Meherabad Hill, where Kitty Davy taught her typing and shorthand.
When the New Life began in 1949, Baba sent Katie to Bombay to live with Nariman and Arnavaz Dadachanji and to take a job. She went to work for the Japanese Consulate, where under Baba's direction she served for decades as personal secretary to a long line of Japanese consuls general. Bombay never suited her, but she stayed, keeping Baba's strict New Life orders and spending her weekends with him at Guruprasad, Meherazad or wherever he allowed, often entertaining him with mimicry and comic disguises.
After retiring from the Consulate in 1978, Katie rejoined the resident women mandali at Meherazad. She helped her sister Goher in the clinic, giving injections and dressing wounds, and looked after the Meherazad kitchen for the rest of her life. A gifted raconteur, she welcomed pilgrims on Mehera's porch and abroad with stories of her life with Baba, and in her last years recorded them for a video project; she often said she felt she had never left the New Life. She also published a cookbook, Cooking with Katie (2001). Katie died at Meherazad on 29 May 2009, aged 89, was cremated the same day at Meherabad, and her ashes were interred near Baba's Samadhi on Meherabad Hill.