But the selection came with an important caveat. Hagen is playing for the women's squad of famed German club Bayern Munich, and will be under contract with that team through the end of June.
Riley said he is prepared to wait for Hagen's arrival.
"I think Hagen would have gone No. 1 in the draft had she not gone to Bayern Munich," the coach said.
The other important Independence selection was Santa Clara goalkeeper Bianca Henninger in the third round, 14th overall. She was rated as the top goalkeeper in the draft.
It is likely that Henninger will start for the Independence during the Olympics if, as expected, regular starter Nicole Barnhart goes to London.
"She's going to have to go into the deep end, and probably straight away," Riley said of Henninger. "She's got the experience to be able to do it - she's poised, she's a good shot-blocker, she organizes well."
The Independence also drafted forwards Danielle Foxhoven (Portland) and Jasmyne Spencer (Maryland), and defenders Courtney Goodson (UC-Irvine) and Toni Pressley (Florida State).
Goodson was one of only two draft picks leaguewide who was in the room, and she was thrilled to be part of the occasion. She said she looks forward to playing for Riley.
"I know that [he] is amazing, one of the best coaches in WPS," she said.