Scott attended Canyon del Oro High School in Arizona which also featured a talent of future major leaguers at the time; Ian Kinsler, Chris Duncan, Shelly Duncan & Brian Anderson. Hairston then attended Central Aizona College with Kinsler, getting drafted by the Arizona Diamondbacks in 2001. He would hit at least .300 all but once, in eight minor league seasons.
In 2004 he made the Diamondbacks and became the teams main second baseman batting .248 with 13 HRs & 29 RBIs. He spent most of the next two years in the minor leagues returning for 76 games in 2007. That July he was traded to the San Diego Padres and hit 8 HRs while batting .287 in 31 games the rest of the season. By this point he became a full time outfielder, getting in to 112 games in 2008 as the Padres fourth outfielder.
That June the Padres set a record by becoming the first team in history to win four straight games by a 2-1 score. In the record setting fourth game, Hariston hit a walk off game winning HR against the New York Mets & Pedro Feliciano for the 2-1 record setting victory.
Midway through the 2009 season he was traded to the Oakland A's but returned to San Diego for the next season.
In 2010 he was a team mate along with his brother Jerry, both playing as reserves with the Padres. Scott played in 104 games batting just .210 with 10 HRs 10 doubles & 36 RBIs. In 2011 he signed with the New York Mets as a free agent.
He was used right away making his Mets debut on Opening Day as a pinch hitter. On April 14th he hit a 9th inning two run HR off Colorado's Huston Street although the Mets still lost the game 6-5. In mid June he hit two HRs in the same week both coming on the road in Pittsburgh & Atlanta. On June 29th Hairston tripled & drove in three runs in an inter league Mets 16-9 win at Detroit against the Tigers.
That summer he had a big day at Citi Field against the Philadelphia Phillies. First he doubled home two runs off Cole Hammels & then later hit a three run HR off Danny Baez in the 11-2 Mets rout. His season was cut short in August as he ended the year playing as a utility player in 79 games, batting .235 with 7 HRs 8 doubles & 24 RBIs.
In 2012 Hairston hit his first HR in Philadelphia off Cliff Lee in the Mets 5-2 win there. On April 26th he hit for the cycle in Colorado's Coors Field, although the Mets lost 18-9 Hairston hit a 2nd inning single, then a solo HR in the 4th Inning. In the 5th inning he tripled scoring Ruben Tejada & then doubled in the 6th scoring Tejada & David Wright.
At the end of May he homered in three straight games, gathering up seven hits & seven RBIs in a five game span. At the start of June he homered in back to back games again, the first against St. Louis at Citi Field & then another in Washington against the Nationals. On July 27th, he hit a grand slam HR off the Cubs Casey Coleman in a 17-1 Mets romp over Chicago at Wrigley Field.
In July he hit a pair of HRs in three game set in Philadelphia against the Phillies. Then on July 30th he belted two HRs in a Mets 8-7 win over the eventual world champion Giants in San Francisco. Hairston's HR off Santiago Casilla broke a 6-6 tenth inning tie, leading to the win.
He slumped in August as did the rest of the Mets, after a strong start & being in second place at the All Star break, the team fell to fourth place to end the season.
In September Hairston finished strong with five HRs & 11 RBIs. He finished the year third on the club in HRs with 20 despite only appearing in 134 games (377 at bats). He hit .263 with 25 doubles (fourth on the club) three triples 57 RBIs (tied for fourth) & a .299 on base %.
After thinking about resigning him, the Mets chose to let him go to free agency where he signed with the Chicago Cubs in January 2013.
After hitting just .172 he was traded to the Washington Nationals for a minor leaguer. In 33 games he hit .224 with two HRs & seven RBIs.
In 2014 he was a reserve player on the Nationals playing in 61 games with 1 HR & 8 RBIs batting .208. He signed with the Chicago White Sox in 2015 but was soon released.
In an eleven year career he has 589 hits with 106 HRs 133 doubles 17 triples & 313 RBIs in 864 games.