By Amanda Weston

One year after the Supreme Court decided to let states take a gamble on sports betting, DraftKings said the future is mobile.

"There's something about mobile that lends itself to sports betting in that you can do live betting," Jamie Shea, head of Sports Book Digital at DraftKings, told Cheddar Tuesday. "So you can be betting the game while the game is going on, and you've got instant gratification."

Tuesday marked the one-year anniversary of the Supreme Court's reversal of the Professional and Amateur Sports Protection Act. That decision allowed states make the decision to legalize sports betting.

Just one day shy of the anniversary, Iowa Gov. Kim Reynolds approved a bill doing just that.

"You already have six states that have it legal," Shea said. "You've got Tennessee, you've got Montana, you've got Indiana, Iowa, all with something on the books. And then there's multiple states that are still coming in. They've got legislation that they're trying to pass through."

"The most important piece is that it needs to be mobile and retail, so that people can bet on their phone. They can bet from the comfort of their own home, sitting on their couch with their friends, and then still have that same experience where they can go and bet in a retail book where it may be for March Madness. They're sitting there with their friends and having that great event."

Shea said more than 70 percent of DraftKings' bets are made on a mobile device.

Shea described the pace of legalization as "stop and start," but pointed out that it has only been a year since the Supreme Court's ruling, adding "we're moving pretty fast."

To commemorate PASPA's repeal, DraftKings established "Free to Bet Day" as an annual promotion. This year, the promotion was specific to customers in New Jersey, featuring a free bet of $5.14 and $514,000 in total giveaways to correspond with the anniversary date of May 14.