In 2004, Lee reunited with the original Mötley Crüe line-up to release the double-disc album hits entitled Red, White, and Crüe. They launched a monumental reunion tour to support it, The Red, White & Crüe Tour 2005: Better Live Than Dead, the band's first in six years. They also finished the year number 8 on the top concert money earners list. They played 81 shows and grossed $33 million US (Billboard Boxscore). This figure did not include a tour of Australia in December 2005.

Lee released his autobiography Tommyland in 2004. That year Lee briefly attended, but did not enroll in, the University of Nebraska for a few weeks in the fall of 2004, while filming a reality television show for NBC called Tommy Lee Goes to College. The show featured a "fish-out-of-water" premise as it followed Lee's effort to fit into the collegiate experience, including trying out for the band (as a drummer), taking courses in horticulture, chemistry, and literature, and receiving constant support from a sexy and smart tutor. Lee was also one of the producers of the reality TV show. At the same time, he released his new solo album, Tommyland: The Ride in August 2005. The CD featured the single, "Good Times". His new single, with video to be released soon, is "Hello, Again". This features Andrew McMahon from Something Corporate and Jack's Mannequin.

Tommy Lee was also a guest DJ at WXRK "K-Rock" in New York during the Fourth of July Monster Metal Meltdown in 2005.

He has formed a new band called Rock Star Supernova with Jason Newsted (Voivod, ex-Metallica) and Gilby Clarke (ex-Guns N' Roses). The 2006 season of Rock Star selected Lukas Rossi as the lead singer for Supernova. Dilana, the runner-up, accepted an offer to go on tour with Supernova along with assistance in producing an album of her own.

Lee is also the drummer for the alternative rock band Jack's Mannequin, which has released the album Everything in Transit.

Tommy Lee is a supporter of animal rights and PETA.[1] He recently donated autographed drumsticks to support PETA's campaign against Kentucky Fried Chicken.

In 2006, Tommy launched his own clothing line with apparel manufacturer People's Liberation, to produce jeans, T-shirts and other products featuring graphics inspired by his tattoos. The line is carried by high-end retailers, including Bloomingdale's, Saks Fifth Avenue, Nordstrom, and other boutiques and chains. People's Liberation brand clothing is marketed and manufactured by Versatile Entertainment, which also produces the William Rast brand, inspired by Justin Timberlake.