Former Fox series “Secret Millionaire” looked very much at home on its new network Sunday.

ABC’s relaunch of the feel-good philanthropic skein ruled its hour in key demos while drawing the night’s largest overall audience.

On a busy night for reality bows, Sunday also saw a half-baked start for NBC’s “America’s Next Great Restaurant,” which was an also-ran in the three-network reality show battle at 8. The net fared better but was down year to year with “Celebrity Apprentice,” which led its second hour in all key demos.

Star of the night, though, was “Secret Millionaire,” which averaged a 3.3 rating/9 share in adults 18-49 and 12.6 million viewers overall in the 8 o’clock hour. The Zodiak USA-produced show, which originated in the U.K., gave ABC its best regular score in the timeslot since November 2009 in adults 18-49 and since March 2008 in total viewers.

Auds have looked to the 8 o’clock Sunday hour for uplifting fare in recent years, with shows like CBS’ “Touched by an Angel” and ABC’s “Extreme Makeover: Home Editon.” But with “Home Edition” fading, ABC thought it was worth a shot to give “Secret Millionaire” — which aired for a few weeks in December 2008 on Fox — a six-week tryout.

Similar in concept to CBS’ “Undercover Boss,” which airs at 9 p.m., “Millionaire” sees wealthy businesspeople dole out cash to “unsung heroes” in impoverished areas. And like “Boss,” which typically surges in its second half-hour, Sunday’s preem seg of “Millionaire” hit 13.3 million viewers from 8:30 to 9.

The arrival of “Millionaire” elevated ABC’s entire lineup, which posted its best Sunday average of the year (a winning 2.7/7 in 18-49). “Desperate Housewives” (3.4/8, 11.3 million) was up over its recent outings and edged out “Millionaire” as Sunday’s top show in 18-49. “Brothers and Sisters” was also up but ran third at 10 (2.2/6, 7.5 million).

Elsewhere, the preem of NBC’s “America’s Next Great Restaurant” settled for a 1.6/4 in 18-49 and 4.6 million viewers overall, ranking fourth in a crowded 8 o’clock reality hour. It was followed by “Celebrity Apprentice” (2.7/7 in 18-49, 7.9 million), which placed fourth at 9 o’clock but surged to the lead at 10.

There was some question whether the failure of the civilian edition of “The Apprentice” on Thursdays in the fall would impact the celeb version, but auds turned out in pretty good numbers to see a group that includes Gary Busey, Richard Hatch and Star Jones. Show peaked at 10:30 p.m. with a 3.1/9 in 18-49.

Still, “Celebrity Apprentice” was down about 15% from last spring when it enjoyed a much stronger lead-in from “Minute to Win It.”

At CBS, “The Amazing Race” (prelim 2.7/7 in 18-49, 9.8 million) and “CSI: Miami” (prelim 2.4/7 in 18-49, 10.9 million) both bounced back from season lows opposite the Oscars, while “Undercover Boss” (prelim 2.7/7 in 18-49, 10.9 million) continues to put up solid but unspectacular numbers one year after bursting onto the scene with boffo scores.

Fox was led by “Family Guy” (prelim 3.1/8 in 18-49, 6.3 million) and “The Simpsons” (prelim 2.8/8, 6.2 million).

All shows in the 9 o’clock hour should have an easier time the rest of this month as ABC’s “Housewives” is skedded to air three straight repeats.