A right-handed batsman and a right-arm off break bowler, Dharmasena was a member of the Sri Lankan side that won the 1996 Cricket World Cup.

[4] He along with Dulip Liyanage set the record for the highest 8th wicket runstand for Sri Lanka in ODI cricket (91).

[5][6] Following his retirement as a cricketer in November 2006, Dharmasena announced plans to become a competitive umpire, as he wished to remain "close to the game which I love so dearly".

[7] Prior to his retirement, he had already umpired several domestic matches in the Sara Trophy, the major first-class cricket tournament in Sri Lanka.

[2] Dharmasena was named the Umpire of the Year at the 2012 ICC Awards, receiving the David Shepherd Trophy.

[16] In April 2019, he was named as one of the sixteen umpires to stand in matches during the 2019 Cricket World Cup.