Long subsequently joined Conference National club Gravesend & Northfleet on 26 July 2006. He made his Gravesend debut as a substitute in a 1–0 victory over Woking on 21 October 2006. Long scored his first goal in the same season away at Kidderminster Harriers in a 2–1 victory on 3 March 2007. He made 31 appearances during the 2006–07 season. Long continued featuring regularly under Liam Daish in the club's 2007–08 campaign. He played 47 games in all competitions and scored 14 goals from midfield, including successive braces against Grays Athletic and Weymouth. Long was also a regular player in the club's successful FA Trophy campaign the same season, playing in all seven games, including the 1–0 win against Torquay United in the final at Wembley Stadium on 10 May 2008. The 2008–09 season saw Long play 49 games for the Kent club, scoring four times.