Bryce defeated Janesville schoolteacher Cathy Myers in Tuesday's primary. Former Ryan aide Bryan Steil was the Republican front-runner, facing token opposition in the primary.
Bryce captured national attention with a slick announcement video last year, before Ryan announced his retirement. He's raised more than $6 million, six times what Myers brought in. He won endorsements from Vermont Sen. Bernie Sanders and labor activist Dolores Huerta.
Democrats are optimistic for their chances to pick up the southeast Wisconsin district that Ryan has represented for 20 years. But opponents argue that Bryce's past, which includes failing to pay child support and a 20-year-old drunken-driving arrest, makes him unreliable and unelectable.