For his 2008 campaign, Mr. McKeon collected $86,000 from the military industry for his political action committee and re-election bid. This time, even before the two-year election cycle is over, he has pulled in nearly $400,000, and has emerged as the top recipient of money in both the House and the Senate from military contractors like Lockheed Martin and Northrop Grumman.

Two of his former aides — who now work as military industry lobbyists — cornered him last month at a Capitol Hill reception held to unveil a portrait of Mr. McKeon, painted to honor his former service as chairman of the House Education and Workforce Committee. (He held that spot for only several months, just before Republicans last lost control of Congress, but he still had a portrait commissioned.)

Recognizing the enormous power Mr. McKeon could soon have in helping shape Defense Department policy and spending, military contractors are teaming up with his office to form a new association of military suppliers they are calling the Aerospace Defense Coalition of Santa Clarita Valley, to make sure he can deliver as much money as possible to his district in California, where several of the big contractors already have large operations.

Mr. McKeon, who is known as Buck, has already hinted to industry lobbyists that he wants to push for more spending on unmanned aerial vehicles, which could benefit contractors in his district.

“Buck is a great advocate for our war fighters and for the industrial capabilities that support their mission,” said Hanz C. Heinrichs, a former aide to Mr. McKeon who now represents military contractors like L3 Communications..

One lobbyist who knows Mr. McKeon well and has contributed the maximum allowed by law to his re-election campaign has met with several military contractors in recent weeks as he seeks a way to profit from the rise of Mr. McKeon to chairman.

“I don’t want to count the chickens before they hatch,” said the lobbyist, referring not to the possible Republican takeover but to his possible surge in new clients. “But I would be surprised if it didn’t help me in one way or another. Business should be very good.”