In 2010, the singer came up with a pseudonym Seven Lions. Seven Lions was one of the characters of his favorite book “Latro in the Mist” by Gene Wolfe. The same year, Jeff released an unofficial remix of “Cosmic Love”. Then he remixed “Satellite" from Oceanlab. The artist performed in a contest with a remix of Above & Beyond’s “You Got To Go". The song stayed on the second position of a dubstep chart Beatport for several weeks.
In the spring of 2012, Montalvo embarked on his first big tour UKF Tour with DJs Koan Sound and Gemini. The same year, he made a remix to Above & Beyond’s "On My Way To Heaven".
The DJ’s first EP, Polarize, came out in April 2012 with the assistance of a British label, Viper Recordings. It featured six tracks, which were a combination of such styles as house, dubstep, drum and bass. To record three of these tracks, Jeff invited Shaz Sparks. The album earned positive reviews from the critics.
After showing his demo to Skrillex, Jeff started working on an EP. In the fall, he presented Days to Come, which featured four tracks. To record the promotional track, Jeff invited the famous Australian singer Fiora. Vibe Magazine called Montalvo’s album one of the best electronic releases of 2012. It reached the 10th spot of Billboard Dance / Electronic Albums and came in 13th on Heatseekers Albums. The EP also appeared on iTunes chart. Many clubs wanted to book Seven Lions for private events.
Seven Lions worked with such famous musicians as Armin van Buuren, Above & Beyond, and Gareth Emery. In 2013, Jason Ano filmed a short documentary film about the DJ. The fans got a chance to learn more about the musician and the way he creates his music.
In 2015, the DJ recorded a new EP, The Throes of Winter, recorded with the assistance of Casablanca label. Many tracks were similar in style to the previous EP. The next year, the artist presented a new EP, Creation, which topped Billboard’s Electronic Albums Chart.
In 2018, Seven Lions announced via Twitter about his plans to create a label, Ophelia. He used it for all of his following releases. Several days after the label’s launch, Jeff recorded a new single "Calling You Home". A month later, he presented "Ocean". The new EP, Start Again, came out the same year.
In the fall, the artist recorded the single "First Time" with the assistance of Dabin and Slander. His first dubstep single of 2019 was “Island”, recorded with Nevve. The newest EP, Ophelia Volume 1, came out in March 2019.
