"For the success of the world in Afghanistan, it would be better to recognise this inherent character in Afghanistan and work with it and support it," newspaper quoted him as saying in the interview.
"Eventually, if the world is to succeed in Afghanistan, it will be by building the Afghan state, not by keeping it weak."
Karzai will face re-election next year and some diplomats are concerned that Afghanistan and its donors could face another five years of poor management by Karzai, the New York Times said.
Karzai, who has been in office six years, admitted things could have been handled better in the past but rejected criticism, citing "immense difficulties" that his government has faced.
"What is it we have not gone through?" he was quoted as by the newspaper as saying.
He also called for greater action on Taliban fighters who have made their bases inside Pakistan.
"Pakistan will have no peace, Pakistan's progress will suffer, so will Afghanistan's peace and progress, so will the world's," Karzai said.
"If you want to live, and live in peace, and work for prosperity, that has to happen. The sanctuaries must go, period."
Karzai's remarks came against a backdrop of continued Taliban attacks targeting the Afghan government.
A census official was among four people killed by bomb blasts on Saturday, officials said.
The other three were police officers. At least 17 more people were wounded in the blasts.
Four suspected Taliban fighters were also killed.
Two of the police officers were killed when a bomb planted in a road blew up their vehicle in the southern province of Ghazni, Zia Wali, a provincial spokesman, told the AFP news agency.
The third police officer was killed in a similar blast in the southwestern province of Farah, Khalilullah Ziayee, the regional police commander, said.