Victoria's Secret put her to work in 2008, with a five-city tour to promote the 2008 Swim collection's release in stores; the April–May tour included stops in New York City, Miami, Chicago (where she threw the opening pitch at a Chicago Cubs baseball game), Boston, and Minneapolis. The relaunch of Victoria Secret's sports line, VSX, soon followed, along with her first official campaign as an Angel: promoting the company's fragrance Very Sexy Dare. For the 2009 Victoria's Secret Fashion Show, Miller was chosen to wear the year's "Fantasy Bra," a harlequin design featuring 2,300 white, champagne, and cognac diamonds, and a 16-carat heart-shaped brown-yellow diamond pendant for a $3-million value and 150 total carats. In response to claims that Miller had parted with Victoria's Secret in January 2010, the Chief Marketing Officer for Limited Brands responded, saying the claims were "unfounded and untrue" while adding "we adore Marisa and we will continue to work with her in the future." In late 2010, Miller confirmed she had moved on to other projects.
In a July 2010 interview with Forbes, Miller explained her shift in focus from modelling to becoming a celebrity brand herself. For that reason, she moved to promoting consumer products in line with her own brand and personality. In July 2008, Miller launched a line of shoes she had developed with skateboarder/surfer-oriented company Vans . Miller starred in a 2008 viral video on YouTube with All Star baseball player Ryan Braun for Remington's ShortCut hair clippers
In 2008, Miller became the first spokesperson in motorcycle manufacturer Harley-Davidson's one-hundred-year history. She first partnered with Harley to launch the VRSCF V-Rod Muscle motorcycle and rejoined the company in November 2009 to act as the face of their first "Military Appreciation Month" campaign, featuring Miller as a classic pin-up in military-themed advertisements and online content. 2010 found her again working for the company, this time for their "Start Something" campaign, encouraging dreamers to become new riders. Miller represented the rum brand Captain Morgan as the company's "Official First Mate" in advertising, social responsibility communication, and event appearances, starting in 2010.
She also finished first place in The Best Damn Sports Show Period "Smokin' Sixteen" competition in 2008, repeating her 2007 win over competitors such as Gisele Bündchen and Adriana Lima. Miller ranked second in AskMen.com's "Top 99" for 2010, after ranking third in 2009, ninth in 2008, twelfth in 2007, and fourteenth in 2006. She added to her popular accolades with the "Hot N' Fresh" award at the second annual Spike Guys' Choice Awards.