The burly midfielder has inked a two-year deal with the Toyota Shuttles and leaves in a week.
He signed off with a robust showing in his final outing for Otago.
The 27-year-old was one of the best for the province, but Canterbury took over in the second half and won the NPC final 36-28 in Christchurch on Saturday.
"I’m really proud of the boys," he said.
"We never gave up. Canterbury just had too much momentum in the second half.
"I guess if we were going to learn from them, we just needed to take our chances a bit more in the first half.
"But all credit to Canterbury’s defence and their attack in the second half."
Canterbury were clinical when they entered the 22m and their defence, which has been strong all year, proved formidable again.
Umaga-Jensen scored early in the game, though.
Lock Will Tucker got in behind the defence and popped a pass to loosie Christian Lio-Willie.
Halfback Dylan Pledger carried it on and made a strong run into the 22m.
The ball was recycled quickly and Umaga-Jensen muscled his way over.
The first 20 minutes were actually very promising for Otago, but Canterbury were able to slow the pace of the game and wrestle control of the fixture.
"I didn’t think they were going to broadcast it on live television as I was going to wait for later," he said.
"But that’s my next journey, my next opportunity.
"It is bittersweet. I love this team. I love where we’ve come from and what we’ve been able to achieve over the last five or six years.
"But that’s all part of it. You just want to leave the jersey and the organisation in a better place."
He has done that.
Otago have been battling for too long but this season they played a sparkling brand of rugby which had some punters suggesting they were the favourites for the final.
"I’m glad to have been a part of that. It’s going to be tough not being able to play in the blue and gold.
"Hopefully we keep this momentum going and hopefully the Otago stays on top."
He has not ruled out a return to the province. He has played 30 games for Otago and is quite keen on reaching 50.
He has also clocked 42 games for the Highlanders.
His more immediate future involves catching up with his twin brother, Peter, who plays for the Kintetsu Liners in Japan.
"Funnily enough, we’re actually playing the first round-robin game against each other."
