Jones was a restricted free agent in the 2007 offseason. He was tendered a contract by the Miami Dolphins on March 2.
On April 13, the St. Louis Rams signed Jones to an offer sheet. Less than a week later, Dolphins general manager Randy Mueller announced that the team would not match the offer sheet and Jones became property of the Rams in exchange for the 225th pick in the 2007 NFL Draft. The contract was worth $5.585 million over five years. It included a signing bonus of $1.175 million and salaries of $510,000 in 2007, $700,000 in 2008, $1 million in 2009, $1.1 million in 2010, and $1.1 million in 2011.
In 2007, Jones broke the Rams record for highest punting average in a single season, punting 78 times for a 47.2-yard punting average. The previous record of 45.5-yard punting average lasted 45 years after being set in 1962 by Danny Villanueva. In 2008, he became the first NFL punter to average at least 50 yards per punt since Sammy Baugh in 1940. He was voted second-team All-Pro and a first alternate to the Pro Bowl. For the second straight year, he was voted an alternate to the Pro Bowl in 2009. In 2009, he broke the Rams career gross average punt record with a 48.0-yard average, surpassing the 44.3-yard average established by Danny Villanueva from 1961 to 1964. In the 2010 season, he finished with 94 punts for 4,276 net yards for a 45.49 average. In the 2011 season, he finished with 105 punts for 4,652 net yards for a 44.30 average.