Atar is a first generation Israeli of Moroccan immigrants who settled in Tirat Carmel. During his adolescence, he played football for the Maccabi Haifa youth club. For many, he is one of the greatest players to ever don the Haifa colors.
After playing eight seasons for Maccabi Haifa and winning three titles for the club (The Toto Cup, and the Israeli Cup twice - one of which as both a Cup and a championship title at the same year), he joined the local rival team - Hapoel Haifa for four seasons, before being signed off to Beitar Jerusalem. At Beitar he played only one match before being injured, which rendered him unable to play during the rest of the season.
In the next season, Atar moved to Hapoel Petah Tikva for a single season, before moving back to Hapoel Haifa and a few months later back to Beitar Jerusalem, where he became one of the most popular players. In 2000 he returned to Maccabi Haifa, winning two championships. Atar left Haifa for Maccabi Netanya before the 2002/03 season, the last team in his professional career as a player.
During the season in Netanya, Atar was injured and decided to retire from his career as a player. He quickly signed as assistant coach in Netanya, first alongside Gili Landau and later on Eli Cohen. At the end of the 2003/04 season, Cohen has left the club, and Atar was chosen as the club's head-coach. Even though the M.C Netanya was relegated at the end of that season to the second league in Israel, "Liga Leumit", Atar remained in his position and helped the club return to the Premier League after only one season. In 2006, Atar was sent home by Netanya's new manager, Eyal Berkovich, and proceeded to move and coach Maccabi Herzliya, from which he was fired after only 8 league games before returning to Netanya, later guiding the club to the second place in the Israeli Premier League, and the UEFA Cup Qualifying rounds.
In September 2008, he signed for Beitar replacing Shum. Later that year he won the Israeli Cup, but was dismissed and replaced by Shum.
On September 29, 2009, Atar returned once again to Maccabi Netanya, making it his 3rd stint as the manager of the club. On May 7, 2011 he broke Netanya's undefeated streak from 1971 as he managed the team for 16 straight games without losing a single game.
On April 23, 2012 he signed a two years contract for his home club of Maccabi Haifa. In November 13 he was sacked from Haifa.
On March 19, 2013 he returned to Maccabi Netanya for his 4th stint as the manager of the club.