In taking over as the state’s chief law enforcer, Andrew Cuomo faces the daunting challenge of building on the reputation of his predecessor, Governor Spitzer, while distinguishing himself in a political environment that the new governor is sure to dominate.

With his father — a former three-term governor of New York — standing by his side, Mr. Cuomo could barely contain a smile as he took the oath of office as state attorney general yesterday.

The road to Albany had not been easy for the 49-year-old former federal housing secretary. He first sought statewide office in 2002, losing a bitter Democratic gubernatorial primary to the state comptroller, H. Carl McCall, who was then defeated by Governor Pataki. Mr. Cuomo faced more attacks in running to succeed Mr. Spitzer this year, but he prevailed over Democrat Mark Green and a Republican, Jeanine Pirro, whose campaign was marred by a federal investigation and a marital soap opera.

Heading into office, Mr. Cuomo has pledged to tackle Medicaid fraud while helping Mr. Spitzer implement far-reaching ethics changes in Albany. One big question is whether the new attorney general will be able to stand out from the old.

That Mr. Cuomo is following a man who during two terms redefined the office of attorney general may be only half of his challenge. “The further difficulty is that legendary attorney general is now the governor of the state,” the dean of Baruch College’s School of Public Affairs, David Birdsell, said.

In promising an aggressive campaign to dismantle a culture of corruption in Albany, Mr. Spitzer is delving into an area that Mr. Cuomo has also claimed as a chief goal. “The major question is to what extent this will be branded an initiative of the governor’s, as opposed to the attorney general,” Mr. Birdsell said.

Mr. Cuomo campaigned often with Mr. Spitzer, but he has indicated that his priorities will be different from those of his predecessor. While Mr. Spitzer made his name prosecuting white-collar crime on Wall Street, Mr. Cuomo has listed public corruption and Medicaid fraud as his top targets.

The new governor has said he has no problem with that. “He will forge his own path,” Mr. Spitzer said of Mr. Cuomo last month.

Nonetheless, Mr. Cuomo is inheriting a slew of big cases from Mr. Spitzer, including those involving the former chairman of the New York Stock Exchange, Richard Grasso, and the former head of AIG, Maurice Greenberg.

Mr. Cuomo took the ceremonial oath of office shortly before Mr. Spitzer yesterday, and later hosted a reception at the attorney general’s office in Albany, delivering brief remarks to a crowd of several hundred people. He echoed the tone of Mr. Spitzer’s address, saying the state needed a new “spirit of ethics and reform” in government and that he has “a role to play” as the attorney general. “I see the attorney general as the great equalizer, using the laws to bring fairness to society throughout, and equalizing the scales of justice and equalizing the playing field,” he said.

He has said he would issue a package of proposals this month, including changes to the state’s ethics and campaign finance rules.