[1] He made his first team debut on 18 March 2000, replacing Matt Hewlett as a late substitute in the 1–1 draw away to Oldham Athletic and soon became a regular squad member.

[4] He was given a new two-year contract while injured,[5] but struggled to re-establish himself at Ashton Gate after returning from injury, having loan spells at Torquay United in January 2003,[6] and Cheltenham Town in August 2003.

He made a total of 21 full and two substitute league appearances in the 2014–15 season, scoring his first goal for the club when he volleyed in a corner in the last seconds of the game against Chelmsford City on 4 April 2015 to claim a 1–0 victory for Sutton.

[18] On 19 October 2016, it was announced that Amankwaah had signed a one-year contract extension with Sutton United and will stay with the club until the end of the 2017–18 season.

[19] Amankwaah made his 100th career appearance for Sutton on 3 December 2016 in a 2–1 win against League Two club Cheltenham Town in the FA Cup 2nd round.

[20] He went on to appear in every round of Sutton's historic run to the 5th round of the FA Cup for the first time ever, including appearances in a 3–1 victory over local rivals AFC Wimbledon of League One on 17 January 2017,[21] a 1–0 victory over Championship side Leeds United on 29 January[22] and an eventual 0–2 defeat to Premier League club Arsenal on 20 February.