1998–2020: Beauty pageants and television hosting

Lachey was crowned Miss South Carolina Teen USA and won the title Miss Teen USA in 1998. She was the first Miss Teen USA from South Carolina and also the first from South Carolina to be named the pageant's Miss Congeniality.^{[citation needed]} She was a host on MTV's The Morning After (2003) and Total Request Live (2003–2007)^[11] and became a New York City correspondent for Entertainment Tonight in 2005. She hosted Miss Teen USA 2004 and Miss Universe 2007 beauty pageants.

After leaving MTV and Entertainment Tonight, Lachey was featured in print and web-based advertising for Bongo Jeans' Spring/Summer 2007 collection.^[12] She launched a makeup line with Flirt! Cosmetics, which debuted in August 2007 at Kohl's department stores.^[13] In May 2006, Maxim magazine ranked Lachey #15 in its annual Hot 100 issue.^[14] She has been featured on the covers of numerous magazines such as Maxim, Vegas, Shape, Parents, People,^[15] and Lucky.^[16]

Lachey was a finalist in E!'s competition to replace Brooke Burke as host of Wild On!.^[9] From 2009 to 2011, she hosted ABC's TV series True Beauty. The series followed 10 contestants who competed for $100,000 and to be featured in People magazine's 100 most beautiful people issue. The series was produced by Tyra Banks and Ashton Kutcher.^[17] Lachey became a co-host of ABC's game show Wipeout in December 2011.^[18]

Early in her career, Lachey had small roles in numerous television shows, including That's Life, City Girls, 30 Rock, The Bold and the Beautiful, Psych, Hawaii Five-O and Maybe It's Me. In 2008, she portrayed Ashlee in the CBS sitcom How I Met Your Mother, in the episode "No Tomorrow". She portrayed Amy in the parody film Disaster Movie (2008) alongside Matt Lanter, Kim Kardashian and Carmen Electra. The film was panned by critics, but was a moderate box-office success, grossing nearly $35 million against a $20 million budget.^[19] In 2009, Lachey and Kardashian shared scenes again, on CBS's police procedural television series CSI: NY.^[20]

In 2011, Lachey had a guest role as Carmen Chao in NBC's sitcom 30 Rock. She played Tracy in NBC's sitcom Truth Be Told (2015), about two diverse couples who are best friends and neighbors. The series ended after one season on December 25, 2015.^[21] On September 6, 2017, Lachey was announced as one of the celebrities who would take part in the 25th season of Dancing with the Stars, competing against her husband, Nick. She was paired with professional dancer Maksim Chmerkovskiy.^[22] Chmerkovskiy's wife, Peta Murgatroyd, was paired with Nick. On October 30, Lachey and Chmerkovskiy became the seventh couple eliminated from the competition, finishing in joint seventh place.^[23]

In 2020, Lachey and her husband Nick were announced as the hosts of the Netflix series Love Is Blind.^[24] Lachey has stated that when producers approached the couple, “they made literally our dreams come true in terms of being able to work together, being able to spend time together, making our marriage stronger ultimately in the end.” ^[25] The couple has hosted every season of the show announced to date.^[26]

2021–present: NCIS: Hawaiʻi and book

On April 30, 2021, it was announced that Lachey was the first to be cast as a series regular in CBS's police procedural TV series NCIS: Hawaiʻi.^[27][28] Lachey joined the cast in her first leading series role as Jane Tennant,^[29] the first female Special Agent in charge of the NCIS: Pearl.^[30] It is a spin-off of the long-running series NCIS, and the fourth series in the NCIS franchise. Filming for the series began on the North Shore of Oahu on June 16, 2021.^[31][32] The series debuted on September 20, 2021.^[29][33]

On July 14, 2021, Lachey announced that her first book, Life from Scratch: Family Traditions That Start with You, would be released on November 16, 2021, by HarperCollins.^[10][34] The cookbook was written by Lachey and Dina Gachman and includes cooking recipes, parenting tips, birthday and date night ideas and personal stories.^[35][36] Lachey also shared in the book how not having a relationship with her mother has affected her approach to certain things, as she used her imagination to create celebrations and milestone markers that became annual rituals for her family.^[35][37] "Instead of constantly saying, 'I don't have a mom to show me how to do my makeup, what not to wear, how to be a good wife or a good mom,' I said, 'You know what? I can start that for my daughter and be that positive influence," she said in an interview with People magazine in July 2021.^[10]

In 2023, she appeared in General Motors' and Netflix's Super Bowl commercial to promote electric vehicles.^[38][39] She was one of the women included on Variety's " 40 Most Powerful Women on Reality TV in 2023" list, with the magazine writing: "Currently on NCIS: Hawai’i, she’s also the co-host of two of the most-watched unscripted shows on TV: Netflix’s Love Is Blind and The Ultimatum. Alongside her husband, Nick, Lachey co-hosted Netflix’s first-ever live reunion (and then second-ever live program), and while it was a bit rocky, technically speaking, she did what she could to salvage it once the cameras finally started rolling."^[40]

As an actress

As a television personality or host