Prior to joining Bloomberg, Ruhle spent 14 years working in the finance industry. While in college, she spent a summer interning for Merrill Lynch.[10] In 1997, she joined Credit Suisse, where she spent six years working in hedge fund sales. During her time at Credit Suisse First Boston, she served as a vice president and became the highest producing credit derivatives salesperson in the United States.[3][11] In 2003, Ruhle joined Deutsche Bank as a credit salesperson covering hedge funds.[12] She ended her eight-year career there as a managing director in Global Markets Senior Relationship Management.[3] While at Deutsche Bank, Ruhle founded the Global Market Women's Network to help women move into leadership roles at the company.[10]
In April 2012, Ruhle, along with Bloomberg reporters Bradley Keoun and Mary Childs, were the first reporters to break the story of the London Whale, the trader behind the 2012 JPMorgan Chase trading loss.[4] Ruhle reported that Bruno Iksil, the London-based trader at JP Morgan, had amassed positions large enough to distort prices in the $10 trillion credit derivative market.[25]
In June 2013, Ruhle wrote a provocative response to Paul Tudor Jones' comments on women in trading for the Huffington Post that elicited responses from both the media and financial industries.[26] In October of that same year, Ruhle sat down with Martha Stewart to discuss social media, blogging, and the creation of the "lifestyle" category.[18]
In 2015, Ruhle produced and hosted Haiti: Open For Business? (2015), a documentary that explores Haiti's emerging market five years after the country was hit by a devastating earthquake.[27] Ruhle also appeared in Shark Land: A Mission Blue and Fusion Expedition (2015), which brings attention to the plight of sharks in Cocos Island, a national park off the shore of Costa Rica.[28]
In 2015, she interviewed then-presidential candidate Donald Trump, who faced backlash in the media after noting to Ruhle that "the World Trade Center came down during [former President George W. Bush's] reign."[16][29] Ruhle's interview with Martha Stewart in 2013 brought an ongoing feud between Stewart and Gwyneth Paltrow public after Stewart questioned the actress's place in the "lifestyle business".[30]
Ruhle was a columnist for Shape.com, the website for Shape magazine.[31] She was featured on the cover of Working Mother magazine in October 2012,[32] as well as Fit Pregnancy on their April/May 2013 issue.[33] She has been profiled by 201 Magazine,[7] Glass Hammer,[10] IWantHerJob,[14] and Business Insider.[34]
After leaving Bloomberg, Ruhle became host of an hour of MSNBC Reports on weekdays,[35] after which she co-hosted the business program Velshi & Ruhle with Ali Velshi, airing on Saturdays.[36]
Ruhle founded the Corporate Investment Bank (CIB) Women's Network and co-chaired the Women on Wall Street (WOWS) steering committee.[37] Ruhle is also a member of the board of trustees for Girls, Inc. New York[38] and a former member of the iMentor Corporate Advisory Board.[39] She is a member of 100 Women in Hedge Funds, the Women's Bond Club and a member of the corporate council of the White House Project, a not-for-profit organization working to advance women in business, government, and media. She also serves on the board and advises for React to Film, an issue-based documentary film series.[40]
On January 27, 2022, she was named new permanent anchor of The 11th Hour after serving as one of several rotating hosts following original anchor Brian Williams's departure from the network in December.[41]
Ruhle was questioned by lawyers in early 2023 regarding a lawsuit by shareholders of sportswear company Under Armour. According to The Wall Street Journal, court documents showed that company founder Kevin Plank gave Ruhle a phone with a special email address to communicate with him privately and at all hours, sent her confidential financial information about the company and enlisted her help to refute concerns about slumping sales. During his deposition, according to the Journal, Plank described Ruhle's role by saying: "She's a confidant. I would give her counsel on her career and she would give me counsel on things I was dealing with that were either banking or media or human nature in relation." In her deposition, the paper reported, Ruhle said she took free trips with Plank on his private plane. When asked if she were acting as a friend or journalist on those trips, she said in her deposition, "I was flying on his plane as myself, Stephanie Ruhle. I'm not really in a category one or the other."[42] The same reporter, Khadeeja Safdar, had previously reported on the relationship between the billionaire and Ruhle in February 2019.[43]