Ranatunga comes from Gampaha, a town twenty miles north of Colombo. He, along with his brothers, studied at Ananda College Colombo where his mother was a teacher. Arjuna's cricketing career started and was carefully nurtured at school. He played cricket for both the junior and senior teams and captained the Ananda College senior team for two years.
A left-handed batsman and useful right arm medium pace bowler, he made his first-class debut in 1981 at the age of eighteen and a year later played in Sri Lanka's inaugural Test match. He went on to score Sri Lanka's first half century in this game.
Ranatunga went on to captain Sri Lanka in 1988, taking control of the national team for the next eleven years through one of its most successful periods. He was widely recognised as a master tactician and was famous for defending his players at all costs.
Ranatunga's weight was also notable, and gave rise to an incident during a game played in humid conditions when he called for a runner, claiming that he had "sprained something". Opposition (Australian) wicket-keeper Ian Healy, responded that he could not get a runner for being "an overweight, unfit, fat cunt", a comment picked up by the stump microphones and broadcast on television. Ranatunga was known for controversially calling a runner during long innings due to his level of fitness. In the finals of the One Day triangular series in Australia later in the 1995/6 Season, Ranatunga instructed his players not to shake the Australian players hands.
Ranatunga is also remembered for his stand in a one day international against England. Australian Umpire Ross Emerson called Muttiah Muralitharan for throwing. (Muralitharan was subsequently cleared by bio-mechanical experts hired by the ICC.) Ranatunga exchanged heated words with umpire Emerson and led his team to a point just inside the boundary line, halting play, until the Sri Lankan management conferred with him and play resumed. English captain, Alec Stewart, was openly critical of Ranatunga's behaviour. In a comment caught on the stump microphone he was heard to say to Ranatunga "Your conduct today has been appalling for a country's captain
The Sri Lankan national team were considered perpetual underdogs but this image changed completely during the 1996 Cricket World Cup, when Sri Lanka defeated tournament favourites Australia to win it under the captaincy of Ranatunga. This victory, for which Ranatunga was a pivotal part both as batsman and captain, has ensured that Sri Lanka are no longer underestimated on the world cricket stage.
He is noted also for his repeated intense criticism of the Australian team, especially his longstanding rivalry with Shane Warne. While this saw him a maligned figure among the Australian public, his ability to lead the long-standing minnows of world cricket to a World Cup win - over Australia in the final - is arguably one of the greatest displays of captaincy in the history of cricket. Australia were renowned for intimidating their opponents by any means possible, and Arjuna's ability to take on and rattle the team of renowned sledgers, inspired his players to have the self-confidence to stand up to Australia in an era where no other sides could. .
Ranatunga lost the national team captaincy in 1999 after Sri Lanka's poor showing at the World Cup in England, although he was chosen as one of five Wisden Cricketers of the Year for that year. He retired from playing cricket in 2001.