Obama will appear in a press and online campaign above the headline "Be the change. Mentor a child".
There may also be a companion video clip that can be watched online. The campaign, produced on behalf of ServiceNation.org, is timed for National Mentoring Month, which has been observed each January since 2002.
The press ad also features an excerpt from a speech Obama gave in Colorado in July, which begins, "We need your service, right now, in this moment -- our moment -- in history."
Obama's appearance in the campaign is indicative of his high public profile since being elected the 44th president on Nov 4, which has led to US commentators observing that he has crafted a more prominent public face than is typical for presidents-elect.
The mentoring campaign will appear as images of Obama continue to turn up on commemorative coins and plates, the covers of magazines, books and DVDs, and plaques, T-shirts and posters reproducing the front pages of newspapers that reported his election.
In September Obama appeared at the ServiceNation Summit in New York, opened by Mayor Michael Bloomberg, alongside Senator McCain.
The two spoke in depth about their views on the role of citizenship and service in post-9/11 America.
The summit also included keynote addresses by California Governor Arnold Schwarzenegger and Hillary Clinton.
Obama is not the first president-elect to appear in public service advertising.
In December 1992, Bill Clinton appeared in a TV ad that encouraged drinkers to have a designated driver, which was made available to broadcast television networks to run from Christmas to New Year's Day.