Naveed Ahmed, 27, of Tampa, US, wrote a programme that helped a group of scammers bombard mobile phones with unsolicited text messages.
Recipients were told they had won gift cards for an electrical retailer that could be claimed by visiting a website.
He was sentenced to two years probation and can continue to work with computers monitored by probation officers.
Contact information harvested by the scam was submitted to Internet Cost Per Action networks, which are companies that gather personal information and pay for submissions.
ICPA networks are legal - but the way Ahmed and his group obtained the details they submitted was not, said Assistant US Attorney Jimmy Kitchen.
Ahmed is thought to have earned more than $2,000 (Â£1,400) a week between September 2011 and February 2013 by taking part in the scam, according to the Associated Press.
It is believed the money raised was channelled though a Swiss bank account controlled by a so far unidentified co-conspirator.
Ahmed was one of 12 people charged for advertising their computer skills for illegal use on a cybercriminal marketplace which was shut down by the FBI in July.
Ahmed told the judge: "I know my actions were irresponsible... I had this naive, immature view of being invincible."
Defence lawyer Melvin Vatz said Ahmed was "a man of considerable intelligence" who had "succumbed to directing those talents in the wrong way".
A computer expert has avoided jail after being convicted of helping to send millions of spam messages.