Teboho Stephen 'Oupa' Mohoje played for the Free State Cheetahs at the 2007 Under-18 Academy Week and the 2008 Under-18 Craven Week. He then progressed to the Under-21s, playing for them in 2010 and 2011.

Mohoje made his first-class debut on 31 August 2012 when he had a loan spell at Griffons in the 2012 Currie Cup First Division game against Border Bulldogs in East London.

Mohoje returned to the Free State Cheetahs and made five appearances for them in the 2013 Vodacom Cup.

During his time at the Free State Cheetahs, he also played for the university side of the UFS Shimlas in the Varsity Cup competitions in 2011, 2012 and 2013 (as captain). In 2013, he was voted the "Player That Rocks" for the competition.

He was included in the Toyota Cheetahs' squad for the 2014 Super Rugby campaign, making his debut as a replacement for Jean Cook against the Chiefs at Free State Stadium on 5 April 2014.

In May 2014, Mohoje was one of eight uncapped players called up to a Springbok training camp before the 2014 mid-year rugby union tests. He made his Test debut on 28 June 2014 against Scotland in Port Elizabeth, taking to the field as a replacement for Duane Vermeulen.

In 2015 he made a Springbok appearance on 11 July against the World XV in Cape Town as a substitute for Eben Etzebeth, and a week later, in the Rugby Championship test against Australia at Suncorp Stadium, Brisbane, he also played from the bench. He missed, however, the selection for the Rugby World Cup 2015 series in England.

He played only 6 of 16 Super matches in 2015 because of a groin injury and 6 of 11 Currie Cup matches for the Toyota Free State Cheetahs.

In 2016, Mohojé was captain of the South Africa 'A' squad, playing a two-match series against touring England Saxons. He was named in the starting line-up for their first match in Bloemfontein but ended on the losing side as the visitors ran out 32–24 winners. He also started the second match of the series, a 26–29 defeat to the Saxons in George.

Mohoje joined the Springboks once again. He played the first match in the French in-coming tour on 10 June 2017 in Durban, where the Springboks defeated the French. He also played the second match on 17 June 2017 in Pretoria.

He made his PRO14 debut on 22 September 2017 against Leinster in Bloemfontein. Mohoje was announced as captain of the Toyota Cheetahs in the 2018/2019 PRO14 season. Sadly, the campaign lasted only 18 minutes when an injury at Thomond Park against Munster sidelined the player for the rest of the season.

In 2022 Mohojé was again on a loan spell with the Griffons. He played in five matches, helping them to win the Carling Currie Cup First Division. The team was undefeated in their nine games – including matches against the Black Lions (Georgia – winning 41-38), Simbas (Kenya – winning 66-33) and the Goshawks (Zimbabwe – winning 48-5), scoring 435 points and 51 tries. The Griffons completed a perfect 2022 season by winning the Carling Currie Cup First Division title in the final against Eastern Province 45-16. They will join an eight-team Premier Division in 2023. The promoted team is part of the Premier Division for two seasons (until the end of the 2024 Carling Currie Cup season).