Career
Early career
Chelsea player and Ghanaian international Michael Essien stated that he was very happy with Baah"s performance and urged the Club to offer him a contract. Baah later returned to Ghana. Asante Kotoko
In March 2010, Baah sustained a broken shin in a Premier League match against Hearts of Oak at the Baba Yara Stadium.
He underwent surgery at the Komfo Anokye Teaching Hospital (KATH) in Kumasi.
In November 2010, he went to Scotland in order to receive assistance with his rehabilitation at Hearts of Midlothian. On 28 November 2011, Gideon rejoined Asante Kotoko.
On 30 November, he played his first match after returning from his long injury layoff for the Asante Kotoko South Carolina Reserves side. On 21 April 2012, Baah played his first league match against Mighty Jets helping Asante Kotoko to a 2-0 victory and scoring in the process.
While with Kotoko, Baah captured two Ghana Premier League titles and one Super Cup.
Football Club Honka
Baah started his spell for Football Club Honka in a form of a loan from Asante Kotoko Football Club of the Ghanaian Premier League. On Saturday 13 March 2013, Baah made his Veikkausliiga debut in a 2-0 away loss to "Turun Palloseura. On 22 March he made his home debut at the Tapiolan Urheilupuisto against local rivals HJK Helsinki.
Baah scored the winning goal on 25 March 2013 in a 0-1 victory over Football Club KooTeePee in the Suomen Cup to take his team through to the next round.
Baah was chosen to the Veikkausliiga team of the Month for April, May, June and July. On 3 June 2013 Baah was acknowledged for his performance in the first round of the Veikkausliiga by being named by SuomiFutis website as one of the top 5 best players.
He scored his first Veikkausliiga goal on 30 June 2013 against FF Jaro where he scored the opening goal in a 4-2 victory. Baah made his Europa League debut on 18 July 2013 in the 2013-2014 Union of European Football Associations Europa League second qualifying round where they lost 1-3 in the first leg to 2012-2013 Ekstraklasa runners up Lech Poznań.
On 24 July 2013, Baah signed a 2-year contract with Football Club Honka.
At the end of the 2013 Veikkausliiga season, he was officially selected as the leagues defender of the year and rookie of the year. Helsingin Jalkapalloklubi
In February 2014 it was announced that Baah had signed a contract to join HJK Helsinki. Upon joining the club he helped HJK qualify for the Europa League group stages in 2014 with a 5-4 aggregate victory over Saskatchewan Rapid Wien.
On 6 November, Baah opened the scoring for HJK in a famous 2-1 victory over Italian side Torino.
On the following match day of 27 November Baah once again opened the scoring for HJK in another 2-1 victory over Copenhagen. New York Red Bulls
On 9 February 2016, it was announced that Baah had signed for American Major League Soccer side, New York Red Bulls.
In 2009, he received a call-up to Ghana U20 national team In October 2015, Baah received his first senior call up to the Ghana national team
He made his debut for Ghana in a 13 October friendly against Canada, coming into the match as a substitute in the 87th minute.