Previously, he was a member of the Arizona Senate representing the 12th District from 2011 to 2017 (numbered as the 22nd District from 2011 to 2013) and a member of the Arizona House of Representatives representing the 22nd District from 2003 to 2011. He was President of the Arizona Senate from 2013 to 2017.
Biggs voted in support of the Tax Cuts and Jobs Act of 2017. After the vote, Biggs said that the bill would "provide much-needed economic relief" to Americans and businesses, claiming "families will be able to save more money to send their children to college. We are already seeing the positive economic impact based on the promise of tax reform. When this bill is signed into law, we will see an even more robust economy."
In 2016, Biggs ran for the United States Congress in the 5th District to replace retiring congressman and fellow Republican Matt Salmon. Biggs defeated Christine Jones by 27 votes, triggering an automatic recount, to become the Republican candidate.
He defeated Democrat Talia Fuentes in November, 64.1% to 35.9%. He was not required to give up his state senate seat under Arizona's resign-to-run laws, since he was in the last year of what would have been his final term in the chamber.
Biggs' primary victory virtually assured him of being the next congressman from this heavily Republican district; the 5th and its predecessors have been in Republican hands for all but one term since 1953.
2010 When Republican Senator Thayer Verschoor ran for State Treasurer of Arizona and left the Senate District 22 seat open, Biggs was unopposed for both the August 24, 2010 Republican Primary, winning with 25,792 votes, and the November 2, 2010 General election, winning with 59,933 votes.
2012 Redistricted to District 12, and with incumbent Republican Senator John B. Nelson redistricted to District 13, Biggs was unopposed for both the August 28, 2012 Republican Primary, winning with 19,844 votes, and the November 6, 2012 General election, winning with 63,812 votes.
State House of Representatives
2002 With incumbent Democratic Representatives Richard Miranda running for Arizona Senate and John Loredo redistricted to District 13, and with Republican Representative Eddie Farnsworth redistricted from District 30, Biggs ran in the five-way September 10, 2002 Republican Primary, placing second with 5,778 votes; Biggs and Representative Farnsworth were unopposed for the November 5, 2002 General election, where Biggs took the first seat with 31,812 votes and Representative Farnsworth took the second seat.
2004 Biggs and Representative Farnsworth were unopposed for the September 7, 2004 Republican Primary; Representative Farnsworth placed first and Biggs placed second with 11,202 votes; for the three-way November 2, 2004 General election, Representative Farnsworth took the first seat and Biggs took the second seat with 51,932 votes ahead of Libertarian candidate Wade Reynolds.
2006 Biggs and Representative Farnsworth were challenged in the four-way September 12, 2006 Republican Primary; Representative Farnsworth placed first and Biggs placed second with 7,793 votes; in the three-way November 7, 2006 General election, Representative Farnsworth took the first seat and Biggs took the second seat with 38,085 votes ahead of Libertarian candidate Edward Schwebel.
2008 With Representative Farnsworth running for Arizona Senate and leaving a House District 22 seat open, Biggs ran in the four-way September 2, 2008 Republican Primary, placing first with 9,800 votes; Biggs and fellow Republican nominee Laurin Hendrix won the November 2, 2010 General election, where Biggs took the first seat with 59,615 votes and Hendrix took the second seat ahead of Democratic nominee Glenn Ray, who had run for the district's senate seat in 2006.
Biggs has gone on record as opposing the issue of net neutrality, and favors FCC Chairman Ajit Pai's plan to do away with governmental protections of the utility. In a letter sent to his constituents in reply to those favoring the continuation of Net Neutrality guidelines, Biggs has said that "the repeal of net neutrality also maintains consumer and anti-competitiveness protections enforced by the FCC and the Federal Trade Commission," and that he "(does) not believe that adding an extra layer of regulations will help to protect consumers. Instead, we should allow the free market to expand the internet and its services." Biggs, incidentally, has accepted campaign donations in the past in the amount of $19,500 from the same members of the Telecom industry that stand to profit from the elimination of Net Neutrality guidelines.
On June 23, 2017, Representative Biggs was one of three Republicans who called for the resignation of Robert Mueller, the prosecutor investigating Russian interference in the 2016 presidential election, on the grounds that Mueller can not conduct his investigation fairly because of events that happened when he had been the acting director of the FBI.
In 2018, Andy Biggs sponsored a bill "designed to let very sick patients request access to experimental medicines without government oversight", which passed in the House by a vote of 267-149. Biggs stated the bill is "not false hope; It is hope."