As the winner of the 1998 "Miss Teen USA" pageant, Lachey (then Minnillo) was awarded the title and honor of Miss Congeniality 1998, which was voted on by her peers. She later went on to serve as a backstage correspondent for "The 50th Annual Miss USA Pageant" in 2001, a judge for "Miss Teen USA" in 2007 and co-host of the 2007 "Miss Universe Pageant" in Mexico City.
In 2003 Lachey started at MTV Networks, where she served as co-host for Total Request Live and MTV Hits. She hosted several MTV specials, including MTV's Prom Date, The Real World San Diego Reunion and Spring Break Celebrity Fantasies. In 2002 she hosted the UK crossover hit Top of the Pops for The WB and also hosted the live finale of UPN's The Road to Stardom with Missy Elliot.
For two seasons, Lachey was the New York-based correspondent for Entertainment Tonight, the #1 syndicated entertainment newsmagazine in the world. During her time with Entertainment Tonight, she reported on the latest news regarding music, film, television and fashion.
Lachey starred in the FOX comedy Dads, executive produced by Seth MacFarlane (Family Guy, Ted), and was on the NBC series Truth Be Told, opposite Mark-Paul Gosselaar. Additional television credits include co-hosting the popular ABC series Wipeout, as well as appearing as co-host on the reality show True Beauty. She also guest starred on Hawaii Five-O, 30 Rock, How I Met Your Mother, CSI-NY and USA's Psych.
Lachey will next be seen co-hosting Top Chef Junior with Curtis Stone, which will debut on Universal Kids in October.