Gardner immediately established himself a place in the first team for Bolton. He came on as a substitute to make his debut against Hartlepool in the League Cup on 25 August 1998, and made his league debut as a substitute again against West Bromwich Albion on 8 September 1998. In this game, Bolton were reduced to 10 men after the sending off of Guðni Bergsson shortly after Gardner came on, but he scored a late winner to give his team a memorable 3–2 victory over West Brom. He made 22 appearances, half of them starts, in his first year while scoring three goals. In his second season, 1999–2000, he established a place in the starting eleven, starting 23 of 26 games, that he has held on to since. Although Gardner suffered a cruciate ligament injury that took him out of action at the end of the season, he made a full recovery, and was able to return to the starting line-up in 2000–01, playing with the promoted Bolton in the Premier League. He was voted Bolton Wanderers F.C. Player of the Year for the 2005–06 season by the club's fans. Due to a knee injury, Gardner did not make his first appearance in the 2006–07 season until December. In November 2007, he scored his first goal at club level in nearly five years when he opened the scoring in Bolton's 2–2 draw against German giants Bayern Munich at the Allianz Arena in the UEFA Cup group stage. A year later after being moved from a wing-back role back into midfield he scored in the Wanderers 2–0 win over local rivals Manchester City. Gardner made his 400th appearance for Bolton in a 3–0 defeat to Fulham on 27 April 2011. On 24 May 2011, he was in discussions to extend his Bolton contract into a fourteenth year. Gardner rejected a move to West Ham United favouring to sign a new one-year contract at Bolton, which he signed on 5 August. He made four league appearances at the beginning of the next season but was sent off for two bookable offences in Bolton's 3–1 defeat at Swansea City on 29 October and then suffered an injury, making no further appearances that year. At the close of the January 2012 transfer window, he wasn't named in Bolton's twenty five man Premier League squad for the second half of the season meaning he would play no further part in the league campaign. It was later revealed that he had been omitted due to having had an operation on his knee that the Bolton medical staff could not guarantee he would recover from in time to play again that season. It was announced on 18 May 2012 that Ricardo had left the club in line with the expiration of his contract. At the time, Gardner was the second longest serving foreign player in Premier League history after serving fourteen years at Bolton, only beaten by his former Bolton teammate Jussi Jääskeläinen.
On 8 March 2011, Gardner went to Preston North End on an emergency one-month loan as cover for Phil Brown's side. Bolton manager Owen Coyle said it was a great chance for Gardner to improve his match fitness after only just recovering from injury. He made his debut the following day at the left-back position in the 2–1 loss to Leeds United and played three more games for the club.
Retirement
After the end of his contract with Bolton Wanderers, he spent a year training at his old club, West Ham United and Barnsley to keep up his fitness, and played in two reserve team matches for West Ham but decided to leave England to seek a move to the MLS. He went on an unsuccessful trial at Real Salt Lake where he played for the reserves in a 1–0 win against the Portland Timbers reserves and announced his official retirement in May 2014.
International career
Gardner rose to international prominence following the 1998 World Cup. Gardner has also been an important player for the Jamaican national team for much of the last decade and has earned his place as the team's captain. He was captain for the team between 2005 and 2009. He also Captained the team for one game in 2012 at the 2012 Caribbean Cup.
Coaching career
In December 2015, Gardner was appointed as coach of the Jamaica U-20 team. Gardner resigned as Harbour View FCHead coach in December 2018. In March 2019, Gardner joined the staff of Portmore United F.C. as assistant coach.
