D.C. Council member David A. Catania on Thursday endorsed his colleague, Sekou Biddle, in the April 26 special election for an at-large seat on the council, a big get for Biddle as he seeks to distance himself from Council Chairman Kwame Brown and Mayor Vincent C. Gray.

Speaking on the politics program on WPFW 89.3, Catania (I-At large) called Biddle(D) a “very serious, thoughtful, honest man” and praised his work on education and mental health reform issues.

“Not only do I intend to vote for him, I endorse him,” Catania said in an rushed statement made in the closing seconds of the program.

After Brown was elected chairman, the D.C. Democratic State Committee selected Biddle in January to temporary fill Brown’s old at-large seat pending the special election later this month. But Biddle has struggled to gain his footing in a race that also features former council member Vincent B. Orange, GOP school board member Patrick Mara,Ward 8 activist Tom Brown and former Ward 1 advisory neighborhood commissioner Bryan Weaver.

In recent weeks, as the controversy mounted at city Hall, Biddle has been saddled by his close association to Gray and Brown, both of whom pushed the state committee to endorse him over Orange.

By securing the backing of Catania (I-At large), Biddle can try to redouble his efforts to highlight his independence and reach out to voters who are dismayed with Gray and Brown. On the council, Catania has emerged as a leading critic of both Gray and Brown,

A former Republican, Catania still has a good reputation in parts of Upper Northwest with high concentrations of GOP-leaning voters. Just as importantly for the Biddle campaign, Catania could help it rally support in the city’s large gay community. Catania, a key sponsor of the city’s same-sex marriage law, is one of two openly gay council members.

Catania’s endorsement of Biddle is a blow to Mara. Two years ago, Catania played a key role behind-the-scenes in helping Mara unseat former council member Carol Schwartz in the GOP primary. In his past races, Mara has also worked hard to try to win over gay voters.

Biddle is now being supported by Council members Yvette D. Alexander (D-Ward 7), Marion Barry (D-Ward 8), Mary M. Cheh (D-Ward 3) and Harry Thomas Jr. (D-Ward 5). Council member Muriel Bowser (D-Ward 4) is also backing, although Bowser told the Washington Post this week she also “loves” candidate Josh Lopez, a former advisor to Adrian M. Fenty.

The council members, each of whom have their own effective political operations, will likely help Biddle round up support in various neighborhoods in what is expected to be a low-turnout election. But the support, including Catania’s, could make it easier for the other candidates to portray Biddle as too connected to the city’s political establishment.