Tolbert was stricken at about 8 p.m. Sunday while driving alone near the campaign offices in North Las Vegas. He was taken to nearby North Vista Hospital, where he died. No one else was injured and no accident report was filed, campaign spokeswoman Kirsten Searer said.
Tolbert lived in Harlem and had left his job as the chief lobbyist for New York City's public schools at the state capital in Albany to work for the Democratic presidential nominee.
He had previously worked as chief of staff to Democratic state Assemblyman Keith Wright and in other government and campaign posts.
"I was shocked and saddened to learn about the passing of our Nevada state director, Terence Tolbert," Obama said in a statement Monday. "Terence was a strong force in this campaign, with a positive outlook that brought people together. ... His enthusiasm, talent, and warm heart will truly be missed."
Obama spoke with Tolbert's widow, Freida Foster-Tolbert, to offer his condolences.
Mayor Michael Bloomberg said Tolbert was a personal friend.
"Terence was not only somebody who was one of the most likable people in the world, he was one of the most hardworking people in the world," Bloomberg said. "He had great judgment and a great feel for people, and this really is a great tragedy."
Tolbert worked on the 2005 re-election campaign of Bloomberg, a Democrat-turned-Republican-turned independent, and on the campaigns of Democratic politicians including Sen. Charles Schumer, former Gov. Eliot Spitzer and former presidential hopeful John Edwards.
He also worked at the New York State Senate Minority Program Office in Albany and as a staff member to former New York State Sen. Joseph Galiber, New York State Sen. Martin Connor and Rep. Charles Rangel.
Tolbert became Obama's Nevada state director in July, running the campaign in a state won by Bush in 2004.
Tolbert had worked in Nevada during the 2004 campaign as the state director of America Coming Together, a liberal political action group.
Basil Smikle, a political consultant and longtime friend of Tolbert's who is serving as a family spokesman, said the Obama campaign meant more to Tolbert than any of the other campaigns he had worked on.
"He took his role there very seriously," Smikle said. He may have given all that he had for it."
In addition to his wife, Tolbert is survived by his mother, Carolyn Tolbert.
Associated Press Writer Kathleen Hennessey in Las Vegas contributed to this story.