Vitória Guimarães Born in
Accra, Bernard joined
Vitória de Guimarães' youth setup in 2012, after starting it out at
Feyenoord Ghana. He made his senior debuts with
the reserves in the 2012–13 campaign, scoring nine goals and earning promotion to
Segunda Liga. On 4 July 2014 Bernard renewed his contract until 2018, being promoted to the main squad on the 18th. He made his professional – and
Primeira Liga – debut on 16 August, starting and scoring his side's second in a 3–1 away win against
Gil Vicente FC. Seven days later, Bernard scored a brace in a 3–0 home success over
FC Penafiel. His fourth league goal came on 14 September, netting through a
penalty in a 1–1 draw against
FC Porto also at the
Estádio D. Afonso Henriques. Bernard was linked to a possible move to
Manchester United in May 2015, being also a target of
Juventus and
Valencia CF. He finished his first season in the Portuguese top flight with 30 appearances and five goals, with his side finishing fifth.
Atlético Madrid On 22 July, Bernard moved to
Atlético Madrid on a six-year deal, being immediately loaned out to fellow
La Liga side
Getafe CF for the
2015-16 season.
Vitória de Guimarães (loan) On 18 August 2016, Mensah returned to Vitória de Guimarães on a season-long loan deal.
Kayserispor Mensah spent the 2018–19 season at
Kayserispor on loan from
Atlético Madrid with an option to buy. He played a total of 28 games and scored four goals. Kayserispor made the deal permanent in May 2019.
Al-Tai On 15 July 2023, Mensah joined
Saudi Pro League club
Al-Tai on a free transfer. On 16 September 2023, Mensah scored his first goal from the penalty spot on the 12th minute of the game against
Al-Hazm in the Saudi Professional League. On 21 September 2023, Mensah had a
hat-trick against
Al-Ettifaq in a 3–4 loss. Mensah won the November Player of the Month in the Saudi Pro League beating Cameroonian forward
Georges-Kévin Nkoudou to win the award.
Al-Riyadh On 20 August 2024, Mensah joined
Al-Riyadh.
Al-Nasr On 20 August 2025, Mensah joined
Al-Nasr in the UAE Pro League club. ==International career==