At nine seasons, Jesse Martin had one of the longest tenures on “Law & Order,” which is notorious for its revolving-door cast. Last night, his exit from the role of Det. Ed Green helped boost ratings for the long-running NBC drama.

Martin’s final episode averaged a 3.7 adults 18-49 rating, according to Nielsen overnights, easily winning the 10 p.m. timeslot and finishing as the night’s No. 2 show in the demo, behind only Fox’s “American Idol.”

It was the show's best rating since its 18th season premiere in January, which averaged a 3.8.

“L&O” bettered its season-to-date average of 3.3 by 12 percent, and it also drew 12.6 million total viewers, again second-best on the night and nearly 5 million ahead of its nearest timeslot competitor, CBS’s “CSI: NY” repeat.

Martin, part of the original Broadway cast of “Rent,” is leaving the show to return to his singing roots; he’s filming a biopic about Marvin Gaye.

With Green leaving the force in last night’s episode, Anthony Anderson (most recently of Fox’s “K-Ville”) joins the cast as Jeremy Sisto’s partner, meaning that both detective roles have been recast in the past year.

Meanwhile, Fox was first for the night among viewers 18-49 with a 5.5 average overnight rating and a 15 share. NBC was second at 2.8/7, CBS third at 2.2/6, ABC fourth at 2.0/5, Univision fifth at 1.8/5 and CW sixth at 1.6/4.
 
At 8 p.m. Fox led with a 2.5 average for “Til Death” (2.3) and “Back to You” (2.7), while NBC and CBS tied for second at 2.3, NBC for “Deal or No Deal” and CBS for “Big Brother.” ABC was fourth with a 2.2 for “Wife Swap,” while CW and Univision tied for fifth at 2.0, CW for “America’s Next Top Model” and Univision for “Al Diablo con los Guapos.” "Model" did win the hour in the network's target 18-34s with a 2.3 rating.
 
Fox was first again at 9 p.m. in 18-49s with a season-low 8.4 for “American Idol,” with NBC second with a 2.4 for another hour of “Deal.” ABC was third with a 2.2 for “Supernanny,” CBS fourth with a 2.1 for a repeat of “Criminal Minds,” Univision fifth with a 1.9 for “Pasion” and CW sixth with a 1.2 for the finale of “The Pussycat Dolls Present: Girlicious.”
 
At 10 p.m. NBC took over first place with a 3.7 for “L&O,” followed by CBS with a 2.1 for a repeat of “CSI: NY.” Univision and ABC tied for third at 1.5, Univision for “Don Francisco Presenta” and ABC for “Men in Trees.”
 
Fox also finished first for the night among households with a 9.0 average overnight rating and a 14 share. NBC was second at 7.1/11, CBS third at 5.3/8, ABC fourth at 3.9/6, CW fifth at 2.2/3 and Univision sixth at 2.1/3.