Michelle Obama’s sleepless top aide

Tina Tchen has plenty of qualities that made her a logical choice as First Lady Michelle Obama’s top aide, but here’s one that will come in especially handy:

Tchen sleeps only four hours a night.

Appointed Wednesday as chief of staff to the first lady, Tchen cited a “biological-clock thing” in explaining why she sleeps only from 2 to 6 a.m. “I have the good fortune to not need a lot of sleep,” she said. “That’s been a great gift.”

The other 20 hours a day, Tchen earns a reputation as “driven,” “indefatigable” and “phenomenally brilliant,” according to friends and colleagues.

Tchen, 54, will succeed Chief of Staff Susan Sher, who also is a Chicago lawyer, as is the first lady. All three are longtime friends.

An Ohio native whose parents fled China as communism took hold in 1949, Tchen lived in Chicago for 30 years before President Obama tapped her to direct the White House Office of Public Engagement.

A longtime Democratic activist who supported late Chicago Mayor Harold Washington and former Sen. Carol Moseley Braun, Tchen was a partner in corporate litigation in the Chicago office of major international law firm Skadden, Arps, Slate, Meagher & Flom.

She was a Barack Obama supporter and fundraiser dating to the 2004 Senate race that catapulted him to the national stage.

Tchen, addressing Knox College graduates in June, called it “serendipitous” that years ago she ran into a “tall guy, with big ears and a funny-sounding name … long before others knew who he was.”

Tchen will help advance the first lady’s signature causes — fighting childhood obesity, supporting military families and showcasing the arts — while assisting her in high-profile social events, all during the run-up to campaign 2012.

kskiba@tribune.com