diff --git a/src/learner.cc b/src/learner.cc
index dd40b8352..e3e3439bf 100644
--- a/src/learner.cc
+++ b/src/learner.cc
@@ -287,9 +287,13 @@ class LearnerImpl : public Learner {
         metrics_.emplace_back(Metric::Create(name, &generic_param_));
       }
     }
+
     cfg_["num_class"] = common::ToString(mparam_.num_class);
     cfg_["num_feature"] = common::ToString(mparam_.num_feature);
 
+    auto n = tparam_.__DICT__();
+    cfg_.insert(n.cbegin(), n.cend());
+
     gbm_->Configure({cfg_.cbegin(), cfg_.cend()});
     obj_->Configure({cfg_.begin(), cfg_.end()});
 
diff --git a/tests/cpp/test_learner.cc b/tests/cpp/test_learner.cc
index 6cb910903..fa2a21d4f 100644
--- a/tests/cpp/test_learner.cc
+++ b/tests/cpp/test_learner.cc
@@ -111,6 +111,45 @@ TEST(Learner, Configuration) {
   }
 }
 
+TEST(Learner, ObjectiveParameter) {
+  using Arg = std::pair<std::string, std::string>;
+  size_t constexpr kRows = 10;
+  auto pp_dmat = CreateDMatrix(kRows, 10, 0);
+  auto p_dmat = *pp_dmat;
+
+  std::vector<bst_float> labels(kRows);
+  for (size_t i = 0; i < labels.size(); ++i) {
+    labels[i] = i;
+  }
+  p_dmat->Info().labels_.HostVector() = labels;
+  std::vector<std::shared_ptr<DMatrix>> mat {p_dmat};
+
+  std::unique_ptr<Learner> learner {Learner::Create(mat)};
+  learner->SetParams({Arg{"tree_method", "auto"},
+                      Arg{"objective", "multi:softprob"},
+                      Arg{"num_class", "10"}});
+  learner->UpdateOneIter(0, p_dmat.get());
+  auto attr_names = learner->GetConfigurationArguments();
+  ASSERT_EQ(attr_names.at("objective"), "multi:softprob");
+
+  dmlc::TemporaryDirectory tempdir;
+  const std::string fname = tempdir.path + "/model_para.bst";
+
+  {
+    // Create a scope to close the stream before next read.
+    std::unique_ptr<dmlc::Stream> fo(dmlc::Stream::Create(fname.c_str(), "w"));
+    learner->Save(fo.get());
+  }
+
+  std::unique_ptr<dmlc::Stream> fi(dmlc::Stream::Create(fname.c_str(), "r"));
+  std::unique_ptr<Learner> learner1 {Learner::Create(mat)};
+  learner1->Load(fi.get());
+  auto attr_names1 = learner1->GetConfigurationArguments();
+  ASSERT_EQ(attr_names1.at("objective"), "multi:softprob");
+
+  delete pp_dmat;
+}
+
 #if defined(XGBOOST_USE_CUDA)
 
 TEST(Learner, IO) {