McConnochie, who was part of the Team GB side that finished runners-up to Fiji in the sevens at Rio 2016, was forced to withdraw from the match against Wales on Sunday but has done enough in training to earn a seat on the plane to Japan.
His selection caps a remarkable rise for the 27-year-old winger, who has played just one season of English Premiership rugby with Bath.
Although McConnochie is the only uncapped player in Jones’ squad for Japan 2019, there is also room for three players who made their test debuts in the 33-19 defeat of Wales at Twickenham – flanker Lewis Ludlam, hooker Jack Singleton and scrum-half Willi Heinz.
Owen Farrell, who is one of 17 players with previous Rugby World Cup experience in the squad, will captain the side as expected and is one of 22 U20 Championship graduates in the England squad.
Dan Cole and Ben Youngs are the most-capped players included, having represented England 86 times each. Alongside Courtney Lawes, the Leicester Tigers pair will depart next month for a third Rugby World Cup, having all appeared at New Zealand 2011 and England 2015.
“Today is another step in the progress towards the Rugby World Cup. We have taken the decision to [name the squad] early because of what we learned from previous campaigns,” Jones said.
“We want the squad to know early and now we can get on and be the best prepared England side there has ever been, ready to win the World Cup.
“A lot of good players have missed out, we feel for them, I feel for them personally. But as we know the World Cup is an incredible tournament where opportunities can present themselves and all those players who have missed out have been told they have to be ready.”
England will continue their preparation for Rugby World Cup 2019 with a trip to Cardiff to face Wales on Saturday before a match against Ireland on 24 August and a meeting with Italy on 6 September.
“Every game is an opportunity to improve our game fitness, our team cohesion, and our tactical adaptability,” Jones said. “Each game for us will have a specific purpose.”
Rugby World Cup 2003 winners England will hope to banish the memory of their home tournament four years ago when they became the first host to fail to reach the Cup quarter-finals.
Their Japan 2019 campaign will start against Pool C rivals Tonga in Sapporo on 22 September, and Jones’ team will then face the USA in Kobe four days later.
Matches against Argentina, at Tokyo Stadium on 5 October, and France, in Yokohama a week later, are likely to decide their quarter-final fate.
England squad for RWC 2019
Forwards: Dan Cole, Luke Cowan-Dickie, Tom Curry, Ellis Genge, Jamie George, Maro Itoje, George Kruis, Joe Launchbury, Courtney Lawes, Lewis Ludlam, Joe Marler, Kyle Sinckler, Jack Singleton, Sam Underhill, Billy Vunipola, Mako Vunipola, Mark Wilson.
Backs: Joe Cokanasiga, Elliot Daly, Owen Farrell, George Ford, Piers Francis, Willi Heinz, Jonathan Joseph, Jonny May, Ruaridh McConnochie, Jack Nowell, Henry Slade, Manu Tuilagi, Anthony Watson, Ben Youngs
Photo by Laurence Griffiths/Getty Images Caption: George Ford of England talks with Ben Youngs after the 2019 Quilter International match between England and Wales at Twickenham Stadium on August 11, 2019 in London, England.