WASHINGTON — Patting his notes for emphasis, Sen. Al Franken made an impassioned case: The Internet needs to be free for all, he said, not customized so that big corporations can optimize it.

“We’re talking about whether the Internet should remain an open platform where everyone can participate equally,” Franken, a Minnesota Democrat, said during a Senate hearing last month. “Or whether we hand the Internet over to those who can pay the most for it.”

Franken arrived in Washington known better for his past as a comedian and “Saturday Night Live” performer than for his politics. The senator who’s emerged is something else altogether: a techie.

Franken has steeped himself in debates like net neutrality, the idea that Internet service providers should treat all Internet traffic equally rather than moving some content faster than others. He has also led Senate hearings on so-called stalker apps, questioned big technology companies like Google, Apple and Samsung on their use of fingerprint and facial recognition technologies, and loudly criticized big mergers like ones that would link Time Warner Cable and Comcast, and AT&T and DirectTV.

In doing so, he’s answered one of the main questions that greeted him when he became a senator: What policy areas would he dig in on?