In 1974, incumbent Democratic U.S. Representative Jerome Waldie gave up his seat to make an unsuccessful run for Governor of California. Miller decided to run for the open seat, which had been renumbered from the 14th congressional district to the 7th congressional district in a mid-decade redistricting. He won the primary with a plurality of 38%. In the general election, he defeated Republican Gary Fernandez 56% to 44%, the lowest winning percentage of his career. He went on to win reelection 18 times and never won with less than 60% of the vote.