On 14th May 2020, German news agency Bild reported that Hannover's American youth international Sebastien Soto is set to join Noriwch on a free transfer when his Hannover contract expires, and would sign a three year contract. But because Soto's application for a work permit was denied, he'll be forced to go out on loan for the first year of the deal, and at present there is interest from German, Dutch and Belgian clubs.

Soto made 5 first-team appearances for Hannover after joining in 2018 after rising through the ranks at MLS side Real Salt Lake. He made a positive first impression at Hannover, scoring 17 goals in 24 appearances with Hannover's U-19 team during the 2018-19 season. He was previously with the San Diego Surf before moving to Real Salt Lake in 2016.

Soto made his debut for the United States under-19 team in May 2018, scoring five goals in four matches at the 2018 Slovakia Cup, where he won the Golden Boot award as top scorer. He made his Under-20 debut in September 2018 and played for the USA in the Concacaf Under-20 tournament and the 2019 FIFA Under-20 World Cup (scoring four goals).

Soto's transfer to Norwich was confirmed on 28th July 2020 with Soto signing a three year contract. Work permit challenges would see him loaned out and he was pictured training with Dutch side Telstar. The loan was confirmed on 26th Auguist 2020.

“It’s a proud feeling. It’s super exciting to join Norwich City,” said Soto. “The facilities here are really impressive. From the minute I arrived here, it’s given me a lot of excitement. Being a young player, it’s nice to hear that the head coach gives us a chance. It was a big factor in me moving here. I’m striker that loves scoring goals. I love being part of a good team that plays good football.”

Soto scored a brace on his full debut for Telstar as they thumped Den Bosch 6-1 on 28th September 2020.

On 4th November 2020 he received his first call-up to the full USA international squad after scoring five goals in seven games for Telstar. USA manager Gregg Berhalter gave Soto his full international debut on 16th November 2020 coming on as a 77th minute substitute in a friendly against Panama in Austria and scoring two goals to give the USA a 6-2 victory.

His loan to Telstar was ended early in January 2020 with Soto netting seven goals in 12 games in the Eerste Divisie. He returned to Norwich and was granted a work permit due to his international debut. He will join up with City's U23 side, although Daniel Farke did admit the 20-year-old could be handed an opportunity in the first-team if he impresses in training.  He ended up making three appearances for the Under-23s.

On 1st March 2021 Soto was called up to the USA's Under-23s for their participation in the Concacaf Men’s Olympic Qualifying tournament from March 6 to March 31. If they are successful they would compete at the Tokyo Olympics. His mistake went punished as USA's youth side lost to Mexico in the final group stage and were then knocked out of qualifying against Honduras. 

On 3rd July 2021 he signed for FC Porto on a season long loan. Porto's deal for the 20-year-old is understood to include an option to make the deal permanent, that fee is reportedly around €1million, according to reports in Portugal.  Soto will initially link up with the club's B team but will be handed opportunities to impress first-team boss Sergio Conceicao. 

Soto made just eight appearances in the Portuguese second tier, scoring once and his loan was cut short by Norwich who promptly loaned him to Sottish side Livingston on 26th January 2022 .Livingston manager David Martindale said "He comes with a fantastic CV and I'm looking forward to seeing how he adapts to Scottish football. Sebastian was on our radar in the summer, but we missed out to FC Porto, but it hasn't quite worked out for him over in Portugal. He has made a lot of sacrifices to make the move to Livingston happen, so it's refreshing to see the desire from the player to come up and play with ourselves in the Scottish Premiership." He failed to score in 14 top flight appearances for Livingston. 

On 9th July 2022 he played 30 minutes of a trial game for Barnsley against Crewe. He appears to not be in Dean Smith's plans for the 2022/23 season.

On 25th August 2022, Soto transferred to Austrian topflight side SK Austria Klagenfurt, signing a three year deal. Soto said "Those in charge at Austria tried very hard for me and showed me what goals the club has set itself for the next few years and what role I should play. I had a good feeling right away and I'm happy that the transfer worked out. I'm looking forward to the team and can't wait to be on the pitch with the other guys. For me, this change is an important step in my career."

Soto left Klagenfurt on 22nd October 2024. He had played 19 games, scoring once.