Ackerman's victory gives the GOP a 41-to-39 edge in the Assembly and the upper hand it lost in December with the defection of Paul V. Horcher, the maverick Diamond Bar Republican-turned-Independent who was recalled in the spring.
Ackerman, 52, will fill the unexpired term of Ross Johnson, now a state senator from Irvine.
With a 12.5% turnout, the final count showed Ackerman winning 77.7% of the vote to Hager's 22.3%.
Long before the polls closed, Ackerman had his plane ticket and his bags packed.
"I'm leaving for Sacramento at 7 a.m.," said Ackerman, a corporate attorney. "Assuming this election gets certified as quickly as everybody thinks it's going to, I'll be sworn in shortly after that and then get to work."
Ackerman will arrive in the Capitol during the harried final days of the session, as a stack of bills await final votes. He said his Assembly colleagues already have sent him copies of "six or seven bills" that could come up for a vote before the session adjourns Friday.
"I've heard the action could be either real light or real heavy. It all depends on how much they get done today," Ackerman said Tuesday afternoon.
Assemblyman Bill Morrow (R-Oceanside) called it "absolutely critical" that Ackerman come to Sacramento to help the Republicans push through a number of last-minute bills.
"We have bills waiting to welcome him as soon as he gets here," Morrow said. "We are talking about the very meat and bone of the Republican agenda."
Although Ackerman favors the recall of Assembly Speaker Doris Allen (R-Cypress), who is considered a traitor by many Republicans, his victory and the GOP majority are not expected to help unseat her as long as she has the complete backing of all 39 Democrats. Allen has hinted that she might resign her speakership, however, and the Democrats have suggested they might back freshman Assemblyman Brian Sentencich (R-Fresno) as her replacement.
But Fuentes said the new Republican majority "could well mean the fall of Doris Allen and the true end of Willie Brown," the former Democratic Speaker the Republicans tried for years to unseat.
"This contributes to her meltdown," Fuentes said. "We have the numbers now and the numbers are there and real."
Ackerman's win has been considered a slam dunk since July, when he swept the primary in the mostly residential and conservative district, which includes La Habra, Fullerton, Brea, Placentia, Yorba Linda, and parts of Anaheim Hills and Buena Park.
Ackerman won 47% of the primary vote but, because he did not win a majority, a runoff was required against Hafner, 56, a Fullerton resident and a clerk at UCI Medical Center who was the lone Democrat. She came in a distant third in July.
(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)
Final Election Returns
72nd Assembly District
100% Precincts Reporting Votes (%)
Richard Ackerman (R): 17,212 (77.7)
Shirley Hafner (D): 4,954 (22.30
* Elected candidate is in bold type.