CNN

WASHINGTON (CNN) - Saying public service is near and dear to her heart, first lady Michelle Obama on Tuesday encouraged Americans to lend each other a hand.

Speaking to nearly 200 employees of the Corporation for National and Community Service, she told the story of how she left a job at a high-powered Chicago law firm to found the volunteer group Public Allies in 1993.

"I could have been some rich lawyer somewhere," she joked, "… writing a check here and there to the Obama campaign."

Public Allies was among first recipients of AmeriCorps grants, one of many programs overseen by the Corporation for National and Community Service. The acting CEO of the corporation, Nicola Goren, who introduced the first lady, praised the Obama administration for what she called "skyrocketing" volunteerism and the passage in April of the Edward M. Kennedy Serve America Act.

The bill, which Goren called the most sweeping public service legislation in 75 years, renews and expands her corporation's programs. It will triple the number of positions in the AmeriCorps program, from 75,000 to 250,000, by 2017, she said. It also includes the Silver Scholars Program, awarding Americans 55 years and older $1,000 for 350 hours of service in a year.

Obama said such programs are more and more possible because seniors are making their 70s and 80s more like their parents' 50s and 60s. "I know with my mom, we gotta keep her moving," she said.

During the speech, Obama expressed understanding for people who might not have the luxury of extra time for volunteering.

"Ironically, in order to do some of that service, you had to have somebody supporting you for that summer you weren't working and you were doing something interesting," she said. "For many Americans, it may seem impossible to squeeze even more time out of the day and do more."

But, she said, families are volunteering more often - a good thing because the United States today needs all hands on deck. Quoting Thomas Edison, Obama said, "Opportunity is missed by most people because it comes dressed in overalls and looks like work."