He achieved the league's highest field goal percentage during the 2017–18 season, his 62.1% career field goal accuracy is the fourth highest in NBA history, and has remained among the top players in rebounds and blocks, leading the NBA in rebounding during the 2021–22 season.

At 15 years old, he was spotted at the European Junior Championships with the Swiss team and joined the Chalon-sur-Saône training center, INSEP, in France.

[13] During his rookie season, he had multiple assignments with the Rio Grande Valley Vipers of the NBA Development League.

[15] In his second season, on November 6, 2015, Capela recorded his first career double-double with then-career highs of 13 points and 12 rebounds as a starter in a 116–110 win over the Sacramento Kings.

[16] On November 29, in an overtime win over the New York Knicks, Capela recorded his third double-double over a span of four games, including a career-high 18 points.

[25] On February 9, 2018, he recorded 23 points and a career-high 25 rebounds in a 130–104 win over the Denver Nuggets, earning his first 20-point, 20-rebound game of his career.

[26] Capela was runner-up for the NBA Most Improved Player Award in 2017–18 after averaging career highs of 13.9 points, 10.8 rebounds and 1.85 blocks.

[27] In Game 5 of the Rockets' first-round playoff series against the Minnesota Timberwolves, Capela had 26 points and 15 rebounds in a 122–104 series-clinching win.

[27][29] On November 5, in a 98–94 win over the Indiana Pacers, Capela had 18 points and 10 rebounds for his sixth consecutive double-double, a career best.

[38] On December 28, 2020, Capela made his Hawks debut, putting up seven points, nine rebounds and two blocks in a 128–120 win against the Detroit Pistons.

[39] On January 22, 2021, Capela recorded his first career triple-double with 13 points, 19 rebounds and a career-high 10 blocks in a 116–98 win over the Minnesota Timberwolves.

[45] In August 2013, Capela debuted for the Swiss national basketball team at the FIBA EuroBasket 2015 qualification rounds.