Šmits made his debut in the Spanish top-tier levelLiga ACB, with Fuenlabrada, during the 2012–13 season, while also seeing action for Grupo Eulen Carrefour El Bulevar de Ávila, in the country’s third-tier division LEB Plata, that same season. From 2013 to 2015, he primarily played for Fuenlabrada's reserve team in LEB Plata sides Fundación Baloncesto Fuenlabrada and the affiliated team Viten Getafe respectively.[3] But, he also earned increasing playing minutes in the top-tier level ACB.
In the 2016–17 season, Šmits won the European-wide 2nd-tier levelEuroCup's Rising Star Award,[4] after shooting 55.1% from the field overall, 60.4% from 2 point field goal range, and 48.8% from 3 point field goal range, while averaging 9.4 points, 2.8 rebounds, 0.9 assists, and 0.6 steals per game,[5] with Fuenlabrada during the EuroCup season.
On 18 September 2017, Šmits signed a five-year contract with FC Barcelona, but stayed on loan at Fuenlabrada until the summer of 2018.[6] On 30 June 2022, Šmits parted ways with Barcelona after his contract with the club expired.[7] Over four seasons with Barça from 2018 to 2022, Šmits averaged 4.6 points and 2.8 rebounds in the EuroLeague, along with 5.2 points and 2.6 rebounds in the Liga ACB, mostly serving as a backup for Nikola Mirotić.
On 3 July 2022, Šmits signed a two-year contract with Žalgiris Kaunas of the LKL and the EuroLeague.[8] On 25 May 2023, Šmits agreed on a three-year contract extension until 2026, with opt-out clauses after each season.[9][10]
Šmits received his first cap with the senior men's Latvian national basketball team in 2014. In 2017, Šmits competed with the Latvian national team at the EuroBasket 2017 tournament, averaging 5.6 points and 2.0 rebounds as the team finished 5th overall.