The show was financed as an experimental series by former UFC owners Lorenzo and Frank Fertitta III, and aired on Spike TV as a last-resort measure to bring mixed martial arts into the mainstream.

Spike TV founder Albie Hecht was searching for affordable sports programming and narrowed his choices to the UFC and the Japanese promotion K-1; a meeting with K-1's head in Japan went poorly, while a later meeting with Lorenzo Fertitta in Las Vegas impressed Hecht, particularly Dana White's 'Vince McMahon'-like personality.

Hecht was not personally a fan of the grappling side of MMA and suggested changing the sport's rules to favor striking, but the UFC refused to alter its format.

Airing right after WWE Raw on Spike TV, The Ultimate Fighter's debut episode retained 57% of Raw's viewers, double the network's usual retention rate.

The Forrest Griffin vs. Stephan Bonnar fight in the season 1 finale is widely regarded as the most influential fight in MMA history and was the first ever MMA event broadcast live on free television; its success directly led to the show's renewal and is credited by Dana White with saving the UFC.

Despite losing the historic season 1 finale fight, Stephan Bonnar was awarded a UFC contract live on air after Dana White declared 'There were no losers in this fight.'

Season 10, featuring YouTube sensation Kimbo Slice, drew record viewership for Spike TV, with his fight against veteran Roy Nelson attracting 6.1 million viewers, making it one of the most-watched MMA fights in history.

Because fight results must be kept secret until episodes air, every fight on the show except the finale is officially classified as an 'exhibition' match sanctioned by the Nevada Athletic Commission, meaning it does not count toward a fighter's official professional record.

During season 7, finalist Jesse Taylor was removed from the show after filming wrapped for kicking out a limousine window in Las Vegas, and his spot was taken by C.B. Dollaway, who had to defeat Tim Credeur for the position.

Season 10 coach Quinton Jackson was filming as B.A. Baracus in the movie The A-Team during production, which postponed his coaches' fight against Rashad Evans by five months.

Several coaches' fights have been cancelled due to injury or other circumstances, including Tito Ortiz needing neck fusion surgery (season 11), Brock Lesnar being diagnosed with diverticulitis (season 13), Dominick Cruz tearing his ACL (season 15), and Shane Carwin suffering a knee injury (season 16).

In TUF: Brazil season 1, the expected coaches' fight between Vitor Belfort and Wanderlei Silva did not happen after Belfort broke his hand while training for it.

Season 15 finalist Michael Chiesa learned that his father had died during the first week in the house but chose to continue competing and ultimately won the season.

Season 15 finalist Daniel Sarafian became the first and, to date, only finalist forced to withdraw from a finale due to injury; he was replaced by Sergio 'Serginho' Moraes, the man he had defeated by KO in the semi-final.