Over a career of four decades, Gen Sarath Fonseka has been the most high-profile and arguably the most tactically successful Sri Lankan army officer.
However, although he has experienced numerous highs, there have been frequent lows.
The "crowning achievement" of his career was wiping out the Tamil Tigers - a victory that came after he was nearly assassinated in 2006 by a Tamil Tiger suicide bomber.
Gen Fonseka was commissioned as a second lieutenant in June 1971 and rose through the ranks while completing training stints across South Asia and in the US and UK.
Over the years he acquired a reputation as a tough battlefield commander and was often in the thick of the action in fighting against the Tamil Tigers. He was wounded in action in 1993.
In the same year, as a colonel, he led a daring operation to relieve troops who at the time were under siege in Jaffna fort in the north of the country.
There are rumours of a rift between the general and the president
The man who is now Sri Lanka's Defence Secretary, Gotabhaya Rajapaksa, was with him during this operation.
The two men who worked so closely together then are today bitter political adversaries and could find themselves on different sides if the general decides to run in presidential elections next year.
In 1995 the general won widespread plaudits for his role in Operation Riviresa - the army's operation to capture Jaffna town from the Tamil Tigers.
One of the low points in the general's career was in 2000 when the strategically important Elephant Pass - one of the few land routes to the Jaffna peninsula - was overrun by hundreds of Tamil Tiger rebels in a surprise attack.
Troops commanded by Sarath Fonseka offered stiff resistance but ultimately had to withdraw. It was a setback that the general was determined to avenge - Elephant Pass was re-captured by his troops in January 2009.
Like President Mahinda Rajapaksa, the general has made no secret of his ardent Sinhalese nationalism and has always displayed a willingness to speak his mind.
Last year he told the media that he strongly believed that Sri Lanka belongs to the Sinhalese, but there are minority communities. They can live in this country with us. But they must not try to, under the pretext of being a minority, demand undue things.
Although he has not confirmed it, the reason for the general's dramatic retirement decision is no doubt closely linked to his disagreement with President Rajapaksa as to who should take credit for the all-out victory against the Tamil Tigers.
If 2009 will be remembered for the end of Sri Lanka's bitterly fought war, 2010 could well be the year of a bitterly fought presidential election.