New York’s Teach for America executive director has taken the term “lead by example” very literally.

Jeff Li announced last week that he is resigning from his top post at Teach For America after less than two years on the job and returning to the classroom as a teacher. The announcement comes just days before his organization is set to announce a campaign meant to encourage alumni to stay in the teaching profession, rather than leave for other professions.

“A funny thing happened along the way as our team thought through this campaign,” Li wrote in an email to TFA alumni teachers on Thursday. “As I personally thought more about teaching beyond two years, and all that can be accomplished by doing so, I became truly re-inspired myself.”

The program that TFA is launching is called “Teach Beyond 2,” a not-so-subtle reminder for its alumni that even though their TFA commitment is technically only two years long, they should consider teaching to be a longer-term pursuit.

More than 40 percent of all TFA corps members in New York City stop teaching once their two-year requirement is fulfilled — a number that is consistent with nationwide TFA studies and only slightly higher than the 50 percent three-year departure rate for all teachers in urban schools. TFA’s critics say the high attrition shows that teaching is merely a resume-builder for some young college graduates before they move onto graduate school programs or higher-paying jobs.

Li’s career path has actually gone in the opposite direction. At 27, he was a highly paid consultant on track to making partner when he decided to enter teaching through TFA in 2003. In 2008, Li won the U.S. Department of Education’s American Star of Teaching award for the achievement gains his students made. He taught math for six years at P.S. 69 in the South Bronx and KIPP AMP, where he was principal when teachers voted to unionize. (A year later, the teachers voted to leave the union again.)

Returning to teaching entails a pay cut, but Li said he has never put compensation first. “I strive not to make too many decisions based on that,” he said.

Instead, he said a love of teaching compelled him back into the classroom.

“I think it was over the last several weeks where it became a real decision for me,” Li said. “This is where my heart is and I just think it’s hugely important work and felt personally fulfilled by the work.”

Li said he didn’t have a new job lined up for the 2012-2013 school year. But finding one shouldn’t be hard, according to his old boss.

“Jeff is one of the more remarkable teachers that I’ve ever met,” said David Levin, co-founder and superintendent of KIPP. “To have him return to the classroom is not only great for his students and their families, but for all the other teachers who will get to learn from him.”

A copy of the email he sent to TFA New York alumni is below.