He played college football for the Tulane Green Wave, and was signed by the Kansas City Chiefs as an undrafted free agent in 2014.

Between 2017 and 2019, he had brief stints with the Chicago Bears, New York Jets, Los Angeles Rams, Tampa Bay Buccaneers, and Tennessee Titans.

[4] Born in Limeira, in the state of São Paulo, Brazil,[5][6] Santos was raised in Brasília, the capital, where his father worked as a pilot for Varig.

Santos was unfamiliar with American football until he moved to St. Augustine, Florida, as a foreign exchange student at age 15.

With the opportunity to earn a college scholarship, Santos remained in Florida, sharpening his kicking skills through high school.

Santos played in all 12 games his freshman year and was named to the Conference USA (C-USA) All-Freshman Team and was honorable-mention All C-USA after leading the Green Wave in points scored while making 13 of his 16 field goal attempts, 32 of his 33 PATs, and handling kick off duties.

[10] At the end of the season, Santos was named consensus All-American[11] and received the Lou Groza Award for the nation's most outstanding placekicker.

On 7 September 2014, he became the first Brazilian born player ever to play in an NFL regular season game[17] in a 26–10 loss to the Tennessee Titans, kicking his first career field goal.

[21] He also made most field goals (25) by a rookie kicker in Chiefs history (tied with Ryan Succop).

[22] In a 21–36 loss to the Cincinnati Bengals on 4 October, Santos kicked a team record seven field goals, including two over 50 yards.

[30] In November, Santos was named AFC Special Teams Player of the Month for the first time after converting 11 of 11 field goals and all five extra points.

[32] After missing much of training camp and the preseason with a groin injury, Santos returned at the start of the regular season.

He started by converting all six extra point attempts in a 42–27 victory over the Patriots on Thursday Night Football.

[36] On 4 December, Santos was placed on injured reserve after hurting his groin in pregame warmups in Week 13 against the San Francisco 49ers.

[40] On 2 October 2018, Santos signed with the Los Angeles Rams to serve as their starting kicker while Greg Zuerlein recovered from a groin injury.

[44] In his Tampa Bay debut, he was perfect on all five extra-point attempts in the 38–35 loss to the New York Giants in Week 11.

[51] On 6 October, in a 14–7 Week 5 loss to the Buffalo Bills, Santos missed four field goal attempts while also making an extra point.

[57] He was elevated to the active roster a day before the 2020 season opener against the Detroit Lions following starting kicker Eddy Piñeiro's placement on injured reserve.

[58] Santos made both of his field goal attempts (35 and 28 yards) and all three extra points as the Bears won 27–23.