India defeated Sri Lanka by six wickets chasing a tough target of 275 runs.
Dhoni scored an unbeaten 91 runs and shared a 91-run partnership with Gautam Gambhir (97).
Yuvraj was the unanimous choice of a select group of experts following his sensational form that helped guide his side to the title. The 29-year-old scored a total of 362 runs at an average of 86.19 in eight innings. Along the way, he also won four Man of the Match awards.
He also took 15 wickets at an average of 25.13 and an economy-rate of 5.02 with his more-than-useful slow left-arm bowling.
"It means the world to me. I have been part of the three World Cups. This is for the nation. Thank you very much, we love you. This cup is for the people," said Yuvraj.
Sri Lanka's inspirational captain Kumar Sangakkara, joint-top wicket-takers Shahid Afridi of Pakistan and Zaheer Khan of India, as well as leading run-scorer Tillakaratne M. Dilshan and Muttiah Muralitharan of Sri Lanka, and AB de Villiers of South Africa were in also in contention for the award.
"But the panel decided Yuvraj’s crucial contributions to his team’s victories with both bat and ball were deserving of the player-of-the-tournament award," ICC said in a statement.
During India's World Cup title victory at Lord's 28 years ago, Mohinder Amarnath won the Man of the Match in the final against West Indies. He scored a crucial 26 in the low-scoring match and then took 3-12.