Ackerman's departure confirmed
It has been speculated weeks on end that Ackermann would take up an offer from Gloucester, but he held back the announcement because he said he did not want to disrupt the Lions' Super Rugby campaign.
However, on Monday morning he revealed that he will depart after the conclusion of the 2017 Super Rugby season in August.
The Golden Lions Rugby Union made a desperate attempt to retain Ackerman, but the lure of the British Pound seem to have been too strong.
"I have come to a crossroad in my career and believe that my coaching journey needs to change in order for me to grow [as a coach]," Ackermann said.
Rudolf Straeuli, Chief Executive Officer at the Lions Rugby Company (Pty) Ltd, said they "honour and respect: the decision and wish him all the best.
"I hope he grows in this new chapter of his career and returns to South Africa an even better coach," Straeuli said.
"Ackers is a valuable asset to the Lions, our community and our culture and more importantly to SA Rugby.
"Johan will be missed, but we have experienced coaches in our structures and that will ensure continuity."
Ackermann will replace former Brumbies coach Laurie Fischer at Gloucester.
"I would be disappointed if anyone doubted by integrity and commitment to the Lions [until the end of the season]," he told a media briefing in Johannesburg.
"It was quite an emotional time to tell the players this [Monday] morning.
"They are more than just players to me, I owe it to them and to the union to be 100% committed until the end of the season.
"My journey elsewhere will only start once the job is done here [at the Lions]," he added.
Gloucester's Director of Rugby David Humphreys was an understandably happy man to have secured the services of his preferred candidate so quickly.
"We're all delighted that Johan has agreed to become the next head coach of Gloucester," Humphreys said.
"He is one of the top coaching talents in World Rugby, and it's a significant coup for the club to recruit someone of his calibre.
"When we first spoke to Johan, we were struck by the enthusiasm and energy he displayed to take up the challenge at Gloucester but, once we had met with him, we knew he was the person we wanted to take the club forward.
"We were particularly impressed by his proven ability to take a team that has under-performed, and turned them into championship contenders. Their year on year progression has been impressive and they are continuing that upward trend this season.
"The way that the Lions play in Super Rugby under his leadership has attracted many admirers around the world, as they have managed to create a winning brand but are also capable of playing an attractive style of rugby."
Ackermann has been outstanding in his time at the Lions and an intricate part of the Lions' resurgence.
He was appointed head coach of the Lions in 2013, after being an assistant coach to the Super Rugby side since 2010.
Under his watch, the Lions to date have played in 112 matches which include 57 Super Rugby games - with 34 wins, 24 losses, one draw, and 55 Currie Cup matches.
He has been short-listed as South African Coach of the Year for the last three consecutive years and coached the SA A side in 2016.
He won seven out of 16 games in his first tenure as coach in 2014 – the most games they have ever won since 2000 and in 2015 the Lions also achieved wins in 9 out of 16 games – the most Super Rugby matches they have ever won since the inception into Super Rugby. In 2016 Ackermann as Head Coach took the Emirates Lions to Wellington facing the Hurricanes in the final of the Vodacom Super Rugby.
As a player, Ackermann represented a number of high-profiled teams in over 180 matches as well as the Springboks in 13 test matches.
The 47-year-old played for The Blue Bulls, the Lions, Griquas and the Sharks during a long and distinguished playing career in South Africa.
He has experience of the Premiership, having enjoyed a spell as a player at Northampton Saints and also played for Calvisano in Italy.
Having retired from playing in 2008, Ackermann was appointed as forwards coach of the Lions in Super Rugby in 2010 where he worked with head coach John Mitchell until 2013 - when he took over the head coach position of the Lions in both Super Rugby and Currie Cup competitions.
Having dropped out of Super Rugby at the end of 2012, Ackermann led the Lions to promotion back into Super Rugby in 2013 and took them to the Super Final last season where they lost to the Hurricanes.
His success at both Currie Cup and Super Rugby level was recognised in South Africa where he was named South African Coach of the Year in 2014, 2015 and 2016 and was coach of South Africa A last season.
During that period, Ackermann has delivered success at team level but has also demonstrated an ability to develop young South African players who have gone on to play for the Springboks.