Ethan Erhahon signed professional terms with the club in the summer of 2017 under the tutelage of Jack Ross, however the youngster had been at Saints since 2005 when he was just 4 years old and progressed through the various age groups within the academy in addition to being one of the first inductees of the national SFA Performance School.
Making his first team debut at the Falkirk Stadium on the final day of the promotion winning 2017/18 campaign still aged only 16 as a vital experience gaining stage of his development, the young midfielder found himself fast-tracked to the first team a few months later when the man who replaced Jack Ross, Alan Stubbs, was sacked after a dismal start to the 2018/19 season. With the transfer window shut and the squad having no left back, new manager Oran Kearney decided Erhahon could fill that role until the next signing period in 4 months time.
Despite having never played this position before, Erhahon performed admirably in this role as he made 23 appearances in his breakthrough season, scoring once against Alloa in the Scottish Cup, and collecting multiple Young Player of the Year awards in the summer of 2019.
During the 2019/20 pre-season, Jim Goodwin replaced Oran Kearney, meaning despite only turning 18 years of age, the youngster was now on his fourth manager as a professional at the club. Although he was used as a left back in the League Cup group stages, Goodwin returned the youngster to the under 20 side and he did not make a Premiership appearance the entire season, although this was a campaign cut short in March 2020 by COVID, by which time Erhahon had moved to Barnsley on loan where he joined their youth team for an assessment prior to a potential transfer which did not transpire as football shut down for several months.
The following season (2020-21) started and finished behind closed doors with Erhahon seemingly still not in the first team picture from the outset, until from nowhere in the sixth fixture of the league campaign, he started against Hibs at St Mirren Park on the 12th September 2020 in the centre of midfield and would be a regular in that position for the next two and a half years, where his probing passing and positional sense helped Saints shifting from a team almost always fighting relegation to a top six European football chasing side.
The youngster scored his first league goal for the club in November 2020 when he smashed a 30 yarder into the top corner at Pittodrie during a 2-1 defeat on a cold Friday night, and followed this up a few weeks later at home to St Johnstone in a 3-2 victory, but the Glasgow born midfielder only scored one more time for Saints, the following season at Livingston as he became more of a ‘protector’ in the side which contained attacking options from the middle of the park such as Jamie McGrath, Conor Ronan and Greg Kiltie.
The 2021/22 season was something of a watershed one for Erhahon, where he seemed to fall out of favour with Goodwin leading to specualtion about his future, but he returned to the first team when the 2013 League Cup winning captain moved to Aberdeen in February 2022 and Stephen Robinson took over as manager of the club. From here, Erhahon played his best football for Saints under the Northern Irishman, with his form improving considerably and importance to the first team growing to the point where his absence presented a significant loss for the starting XI.
With the club and player at stalemate over a new contract which was due to end in May 2023, Saints decided to cash in on their long term asset, and after seventeen years as part of the club, Erhahon signed for English League One outfit Lincoln City on the 31st January 2023 for a reported fee of £350k following 123 appearances in the black and white and 4 goals.