(FORTUNE Magazine) – TALK ABOUT GREAT STARTS. IN BARELY 18 months at the helm of Motorola, Ed Zander has turned one of America's sickliest big companies into one of the hottest. Market share in cellphones, Motorola's marquee business, is up to 18% worldwide, making Motorola a solid No. 2 again after Nokia. The stock price is up too, from $13 when Zander started at the beginning of 2004 to $22 today. Sexy products are selling, the competition is floundering, and ol' Motorola, the sleepy Midwestern company that until recently just couldn't shoot straight (see "Can Moto Find Its Mojo?" on fortune.com), is riding high.

So is Ed Zander the greatest CEO in America--or simply the luckiest?

Consider that the products currently giving Motorola its boost, especially the red-hot, ultrathin Razr flip-top phone, were in the works long before Zander landed from Silicon Valley, where he was president of Sun Microsystems and briefly with buyout shop Silver Lake Partners. The flashy "Hello Moto" ad campaign was also well underway by the time Zander joined. Moreover, Motorola's strategy under Zander is essentially unchanged from when third- generation CEO Chris Galvin called the shots. It's not as if Zander has cleaned house: The executives running each of Motorola's four major divisions--cellphones, police radios, wireless equipment, and set-top cable boxes--were all at Motorola before Zander.

Zander himself professes admirable humility. "I've got to give a lot of credit to the team," he said after releasing triumphant second-quarter earnings. "I don't believe in this whole CEO thing. We're way overrated sometimes."

Still, Zander has made a difference. Numerous new phones were in the lab, but it was Zander who fingered the Razr--and insisted that it and other new gadgets get catchy names rather than numbers. He also has gone outside Motorola for senior-level talent. Most important, he has upped the excitement level at Motorola. Despite being delayed, the iTunes phone Motorola will introduce by September in conjunction with Apple is generating tons of buzz, as is the yet-to-be-released Moto Q phone/ e-mail /PDA device. "He took a hidebound company and infused it with Silicon Valley cockiness," says Paul Sagawa, an analyst with Bernstein Research. "Whether it's Zander or not, Motorola has executed brilliantly." -- Adam Lashinsky