He then had stints in the Premier League with Newcastle United and Watford, before returning to the Netherlands, where he finished his professional career back at ADO Den Haag, finally retiring in 2022.

Born in Leidschendam, South Holland, Janmaat started his senior career in 2007–08, with ADO Den Haag in the Eerste Divisie.

[5] On 21 December 2011, Janmaat scored Heerenveen's ninth goal in an 11–1 thrashing of Eerste Divisie side FC Oss to reach the quarter-finals of the KNVB Beker.

[9] Janmaat scored his first goal of the 2013–14 Eredivisie season on 16 February 2014, converting a pass from Graziano Pellè as Feyenoord drew 1–1 with NAC Breda.

[13] He made his competitive debut on 17 August, playing the full 90 minutes as Newcastle began their league campaign with a 2–0 home defeat to Manchester City.

[32] A picture of a Newcastle supporter giving Janmaat a reversed two-fingered salute, as the Dutchman wheeled away celebrating his goal was widely circulated on social media.

[37] Janmaat made his debut for the Netherlands on 7 September 2012, playing the full 90 minutes in a 2–0 home win against Turkey for the 2014 FIFA World Cup qualifiers.

[40] In the third-place playoff match against host nation Brazil, Janmaat came on as a late substitute for Daley Blind and provided the assist for Georginio Wijnaldum as Holland won 3–0.