FORTUNE — Vicki Thomas, 68, still remembers sitting in her high school auditorium and hearing her principal announce the names of fallen soldiers in the Vietnam War. Throughout her 35-year marketing and advertising career, the Wisconsin-native suppressed memories of watching countless parents sob knowing that their sons were never coming home.

“It stayed with me,” Thomas says. “No matter how confidently I moved from one career to another, that impression stayed with me.”

While earning her undergraduate degree at the University of Wisconsin, the boisterous Thomas actively protested the war. Still, her family encouraged her to seek financial security in the corporate world after graduation. She jokes that she put on her “social climbing shoes” and she built a career that would take her from Madison, Wisc., to Madison Avenue.

After gigs as a television marketing executive for local ABC affiliates in Chicago and New York, Thomas started her own firm, Weston, Conn.-based Thomas and Partners, which specialized in marketing products to aging baby boomers. She says her blue-chip client roster included American Express, Prudential Services, MetLife and Merrill Lynch. She shuttered the firm in 2010, at age 64, with plans to repackage her marketing skills to serve another purpose.

But Thomas didn’t stay “retired” for long. In 2010, Thomas while watching CNN she saw Iraq veteran Dale Beatty talk about his non-profit Purple Heart Homes. The organization helps fellow soldiers with service-connect disabilities find accessible and affordable housing. Beatty, a National Guardsman, was serving in Iraq when he hit a land mine and lost both of his legs below the knee. He started Purple Heart Homes with co-founder and fellow veteran John Gallina in 2008.

For Thomas, her childhood recollections of the affects of war—and her activist instincts—kicked in. “I saw those amputated legs and the ravages of war and it just hit me,” she says. “It has always been a calling and when I saw Dale the voice just grew louder and louder and louder.”

Thomas immediately picked up the phone. She called Beatty and Gallina and offered her services. Purple Heart Homes had only raised $10,000 and completed one project, but Thomas knew that the right marketing plan—and a bit of a makeover for the founders –could help the organization get more attention and increase donations. “Getting John to shave his beard was the hardest,” Thomas laughs, recalling her effort to give Gallina a more clean-cut look.

After joining the Purple Heart team – first pro-bono and then as the director of communications earning a fraction of what she was making as a company founder and CEO — Beatty and Gallina’s story received attention from several media outlets including Time Magazine, ABC, and PBS. The increased attention to their cause secured millions of dollars of in-kind and financial contributions for Purple Heart Homes. With the help of major corporate sponsorships with Home Depot, Citi and Bank of America, the organization has helped 38 veterans secure housing. Thomas, Beatty and Gallina have a goal of finding 500 housing solutions for veterans and their families over the next five years.

Thomas is convinced that her turn toward serving others during the second act of her career does not make her unique. Instead, she is adamant that CEOs of Fortune 500 companies to blue-collar workers are all capable of using their skills for the greater good.

“I think that in life we postpone our passions because we have to make a living,” Thomas said. “As we age in life, we are packaged with skills. I am no more special than anyone else. Everyone must have a passion like I did to make the world a better place.”


Advice For Retirees Considering A Move From Corporate To Non-Profit
“Get out of the way your company taught you think – only about sales, profit and loss. Become a prophet and not a profit.”

What She Wishes She Knew Before The Switch
“Gaining and earning trust and respect — to be able to contribute your wisdom and expertise — it is earned slowly.”

Biggest Challenge
“Having great plans to make the cause a big success and not enough money to make it happen at the pace you want.”

Biggest Reward
“Knowing that you are leaving a legacy or a bit of yourself to help someone or something greater than you.”

Next is a series of articles that looks at executives’ efforts to use their talents and skills to enrich or support the lives of others and upon retirement from professional life.