Born and raised in Mount Vernon, Washington, Mathews graduated from Mount Vernon High School. During high school, he participated in speech and debate events. Mathews graduated again in 2002 from the University of La Verne, in La Verne, California, where he majored in communications and was a speech and debate competitor.

He appeared on the fifth season of VH1’s reality television show, Celebrity Fit Club. During the course of the show, which premiered in April 2007, Mathews lost more than 40 lbs. and helped his team win the grand prize. He was also a guest host on The View on July 17, 2007.

Mathews appeared as a celebrity mob member on seven episodes of NBC’s prime time game show 1 vs. 100 in early 2008.

In 2009, Mathews was a contributing correspondent on The Insider, and hosted a web show with The Insider called Inside Dish With Ross Mathews, where he took his viewers behind the scenes, as an “outsider” in Hollywood. Inside Dish became the official online web-shows for CBS’s Big Brother and The Amazing Race. Also in 2009, Mathews co-hosted GSN’s Big Saturday Night, a weekly game show. His other 2009 appearances included The Howard Stern Show and the 2009 Game Show Awards with Diane. Mathews joined the panel of judges for RuPaul’s drag race with the odd appearance in the earlier seasons and more frequent appearances from season seven onwards. In 2010, Mathews joined the E! Network’s red carpet team, filling in for Ryan Seacrest as co-host with Giuliana Rancic for E! Live From the Red Carpet coverage of the 2011 Screen Actors Guild Awards, the 2010 Emmy Awards, the 2011 Golden Globe Awards, and the 2011 Academy Awards.

In January 2011, Mathews starred in a pilot that he produced and co-wrote with fellow Chelsea Lately round table regular Heather McDonald. Titled Love or Hate, the pilot was made for the E! Network and was executive produced by Chelsea Handler and her company Borderline Amazing Productions. Mathews also appeared in the E! Network’s After Lately, a show about the behind the scenes of Chelsea Lately. By September 2011, Mathews had formally moved on from The Tonight Show, returning for guest appearances, including for the “Woulda, Coulda, Shoulda” skit on December 14, 2011.

Mathews appeared in the fourth episode of the Bravo series Interior Therapy with Jeff Lewis in 2012, in which Lewis redesigned his and his boyfriend’s garage.

On May 7, 2013, Mathews released his book Man Up! Tales of My Delusional Self-Confidence. Mathews was the host of Hello Ross, an interactive talk show on E! from September 6, 2013, until May 16, 2014.

Mathews is openly gay. From 2008 to 2018, he had a relationship with stylist Salvador Camarena. In 2013, the couple appeared in an episode of House Hunters while shopping for a home in Palm Springs.

In 2015, Mathews and Carson Kressley were named as new regular judges for the 7th season of RuPaul’s Drag Race. At the end of 2015, Mathews began filling in as a guest host on Hollywood Today Live, which is syndicated on Fox. He became a permanent host on January 4, 2016. He also starred in the movie Pup Star. The sequel, Pup Star: Better 2Gether, premiered the following year.

Mathews guest-starred as himself in an episode of Mike Tyson Mysteries titled “Unsolved Situations” in 2016.

In 2017, he was the commentator of the Eurovision Song Contest 2017 together with Michelle Visage live for Logo TV. He also commented alongside Shangela on the Logo TV broadcast of the Eurovision Song Contest 2018 final as well.

In 2018, he was announced as one of the eleven houseguests competing on the first American edition of Celebrity Big Brother. He finished in 2nd place, winning $50,000, and was voted as America’s Favorite Houseguest earning an additional prize of $25,000. Mathews also appeared in the second season as part of a Head of Household competition.

On November 28, 2019, he was a field reporter for Verizon 360 at the 93rd Macy’s Thanksgiving Day Parade.