Irani was born on 2 December 1959, in Mumbai. He finished his schooling in St. Mary's School, Mumbai. Irani was dyslexic and had ADHD and had a lisp. He got over his lisp eventually. He studied a 2 year waiter course at Mithibai College in Mumbai. After his polytechnic diploma course, he joined the Taj Mahal Palace & Tower and worked there as a waiter and in room Service. He gradually got promoted and finally worked as a waiter at the rooftop French restaurant, Rendezvous. He worked at the Taj Mahal for two years.
Acting had been a passion to Irani during school and college days. He trained under acting coach Hansraj Siddhia from 1981 to 1983 and adopted professional acting methods. Irani preferred British theatre, and he soon developed different accents.
Irani began his acting career in theatre and moved to films in 2000. Irani gained attention for his role in the 2003 comedy Munna Bhai M.B.B.S.. He later appeared in Lage Raho Munna Bhai for which he received several IIFA award nominations and in 3 Idiots opposite Aamir Khan which earned him a Filmfare Award and a Star Screen Award for Best Actor in a Villainous Role.
Irani hosted the IIFA Awards with actor Ritesh Deshmukh in 2008 in Bangkok, 2009 in Macau, 2010 in Colombo and 2011 in Toronto. He has been on Kaun Banega Crorepati with Sanjay Dutt. He also hosted the quiz show Bollywood Ka Boss. Irani featured in OneTouch Glucose Meters TV commercials in 2015 with Simone Singh.
Irani's mentor was Alyque Padamsee — the veteran theatre actor best known for his role as Mohammad Ali Jinnah in Gandhi. He was introduced to Padamsee by Shiamak Davar. Irani's earliest theatrical appearance was in Roshni where he played a cameo at the Regional Theatre in Versova. He followed this up with serials like Family Ties and Mahatma vs Gandhi, playing Gandhi after the role was turned down by Darshan Jariwala. His most illustrious play till date has been I am not Bajirao which ran for 10 years.
