Still, Porter did not immediately back Warren's presidential bid. For months, speculation mounted over whether she would endorse Warren or California Sen. Kamala Harris, who as state attorney general appointed Porter to oversee a $25 billion settlement with the nation's top banks.
When she finally made her choice in the fall, she called her mentor on the phone.
"I said, 'Elizabeth, if you'll have me, I would like to endorse,'" Porter said, which Warren cheerfully accepted. "And then I said, 'I've missed you a lot.' And she said 'I've missed you too.'"
She made the endorsement public in late October.
Since then, she's made three trips to Iowa, with a fourth planned for the Feb. 3 caucuses. She acts as a warm-up emcee at Warren rallies. She cheerleads volunteers set to knock on doors in the bitter wind, doling out custom-made nail polish in the campaign's "liberty green" and revealing that Warren likes to paint her toes wacky colors.
And she twists arms of undecided voters, in group settings and one-on-one. Kurt Meyer, who chairs the Democratic Party in three rural counties, said Porter spent most of their lunch in Mason City comparing mutual acquaintances and sharing personal memories of Warren before turning to the hard sell.
"She was the closer," Meyer said. "She was to make sure that Kurt Meyer understood in a profound way that the Elizabeth Warren team wants him to get off that picket fence he sits on somewhat uncomfortably and join Team Warren." He publicly endorsed Warren a week later.
Porter's barnstorming is infused with nostalgia. She detours to drive by the Coralville house she lived in as a University of Iowa law professor, proudly noting the wooden fence she built by herself is still standing in fine shape. Her events are dotted with familiar faces -- former colleagues, her old hairdresser, her dad.
Those who don't know Porter personally often know of her, familiar with the now-viral congressional hearing interrogations of JPMorgan Chase Chief Executive Jamie Dimon and Housing Secretary Ben Carson. She has emerged as one of the higher-profile members of the freshman class of House Democrats, a group that has been unusually coveted as surrogates this cycle.
The alliances have largely fallen along predictable ideological lines: moderates who ousted Republicans from swing seats, such as Rep. Abby Finkenauer of Iowa, are backing former Vice President Joe Biden, while progressive firebrands from deep-blue districts, such as New York Rep. Alexandria Ocasio-Cortez, have sided with Vermont Sen. Bernie Sanders. Both candidates deployed their prominent freshman surrogates on the trail in Iowa this weekend.