Randy Wesson, 28, pleaded guilty and will be sentenced in June.
If the federal court accepts the plea, Wesson will get a 30-year prison sentence, even though it carried a maximum of 50 years.
What isn't included in the plea is if investigators find Wesson produced some of the child porn images. He can later be tried for that.
In arrest affidavits, police said Wesson said he sexually abused more than 100 children and had 42,000 child pornography images on his computer.
Wesson also pretended to be the father of the other suspect, Ricardo Lugo, 17.
Police said Wesson enrolled Lugo as a 12-year-old sixth grader at Hurst Hills Elementary, allegedly, so Lugo could recruit victims for Wesson.
The two were arrested in Nov. 2014.
Hurst police say they haven't found any new victims they've been able to identify from the images seized in the searches, so there are no new charges.
Knowing that Wesson pleaded guilty was a big relief to the Hurst Hills community.
Some parents want to see Wesson get the maximum of 50 years, while others said they just want to move on and forget about this chapter.
"It makes me feel a lot better knowing that that guy is not going to be able to harm these children anymore," said Hurst Hills mom Nicole Eggleston.
Defense lawyers and prosecutors declined to talk to media after Wednesday's hearing in Tarrant County.
FOX 4 went by Wesson's home Wednesday, and his mother had no comment.