"I am prepared," Paterson said.
Spitzer resigned Wednesday after being exposed as a client in a high-priced prostitution ring.
"This has been a very sad few days in the history of New York, and for me, it's been sadder," said Paterson, a Harlem Democrat with a home near Albany. "My heart goes out to Eliot Spitzer, his wife, his daughters and his parents."
"We used to call them our other family," Paterson said of Spitzer's parents.
Paterson will be officially sworn in at 1 p.m. Monday, an hour after Spitzer's resignation takes effect.
Paterson acknowledged the strange circumstances of his remarkably swift ascension from leader of the minority Democratic Senate conference in 2006 to the governor's office and leadership of the state's Democratic party just 14 months later.
"It's been a very difficult time," he said. "I did not get to this position in the way most people have, or in the way that most people would like."
Spitzer, who resigned Wednesday after being exposed as a client in a high-priced prostitution ring, was famously abrasive to legislators and was open about his desire to overthrow Senate Republicans. In one noted exchange, he used a profanity to describe himself as a "steamroller" to a Republican lawmaker. Paterson has been praised for his ability to work with legislators of both parties.
"I have spoken with him," Paterson said of Spitzer. "I just told him how sorry I was this happened and how much he still inspires me."
Several Spitzer administration officials are expected to remain with Paterson. Some of Spitzer's top aides, however, have submitted resignations for Paterson to consider.
"The message to the people of New York is that New York state government is still thriving, and we are still serving the people," Paterson said earlier in the day.