He served for eight years (1989-1996) in the Kansas Senate, the last two as majority leader. He was elected to Congress in 1996, and has been reelected five times, putting down any opposition he has faced in the strongly Republican district. In 2003, for instance, he received a stunning 97 percent of the vote. Moran's opponent for the 2006 midterm election was John Doll whom he defeated handily, receiving 79 percent of the vote.

In Congress, Moran has a largely conservative voting record. However, he has a considerable independent streak. The Southwest Daily Times once quoted him as saying, "I will always put Kansans ahead of the pressures in Washington"--a quote he posted on his Web site. He opposed No Child Left Behind, and unlike most congressmen from rural districts, opposed the Medicare prescription drug bill. While criticized by then-Speaker Dennis Hastert for the latter vote, Moran has received numerous awards for his leadership in health care both on the state and national level.

Moran was also noted for his opposition to President Bush's Iraq troop surge. He was quoted as saying that it "does not make sense to send in more troops if the Iraqi people aren't willing to set aside sectarian differences and commit to rebuilding their country."