The Labour leader has said his party will not support open borders and will instead back a "fair" points-based system.
He hit out at the crises facing the health sector as he accused the UK Government of "short-term fixes" and sticking "plasters over problems".
Speaking on BBC Scotland's Sunday Show, Sir Keir was asked about the numbers he would like to reduce immigration to.
He said: "What I would like to see is the numbers go down in some areas. I think we are recruiting too many people from overseas in, for example, the health service, but on the other hand if we need high-skilled people in innovation and tech to set up factories, etc, then I would encourage that, so I don't think there's an overall number here, some areas will need to go down, other areas will need to go up."
At the party's conference last month, he outlined a desire to train and recruit 7500 staff to the NHS across the UK.
The Labour leader was challenged on the workforce crisis facing the NHS, with hospitals struggling to recruit and waiting times reaching record highs.
He responded: "We certainly need to drive those numbers across the whole of the UK, those numbers can go up and I think they should go up, and we need funded places to drive them up. One of the reasons that the NHS is struggling is because it's such hard work. The conditions are so hard because the NHS has been run down."
Sir Keir said he has daily conversations about the lack of staff and the challenges it has on the health sector.
He added: "We should be training people in this country, of course we need some immigration but we need to train people in this country.
"What we've done - this is absolutely classic of this Tory government - is short-term fixes, plasters over problems, never a long-term solution and we're going around and around in circles, every year we have a winter crisis."
He said record high waiting times in Scotland's hospitals should be pinned on "every billboard across Scotland".