diff --git a/src/object.jl b/src/object.jl
index 24bb66d..70ba246 100644
--- a/src/object.jl
+++ b/src/object.jl
@@ -121,7 +121,7 @@ Base.isempty(obj::Object) = _k(obj) === notset && _ch(obj) === notset
 Base.empty(::Object{K,V}) where {K,V} = Object{K,V}() # empty object
 
 # linear node lookup
-@inline function find_node_by_key(obj::Object{K,V}, key::K) where {K,V}
+@inline function find_node_by_key(obj::Object{K,V}, key) where {K,V}
     while true
         _k(obj) !== notset && isequal(_k(obj)::K, key) && return obj
         _ch(obj) === notset && break
@@ -142,9 +142,11 @@ Base.get(f::Base.Callable, obj::Object{Symbol}, key::String) = get(f, obj, Symbo
 Base.getindex(obj::Object, key) = get(() -> throw(KeyError(key)), obj, key)
 Base.getindex(obj::Object{String}, key::Symbol) = get(() -> throw(KeyError(key)), obj, String(key))
 Base.getindex(obj::Object{Symbol}, key::String) = get(() -> throw(KeyError(key)), obj, Symbol(key))
-Base.setindex!(obj::Object{String}, value, key::Symbol) = setindex!(obj, value, String(key))
+Base.setindex!(obj::Object{String,V}, value, key::AbstractString) where {V} = _setindex!(obj, value, String(key))
+Base.setindex!(obj::Object{String,V}, value, key::Symbol) where {V} = _setindex!(obj, value, String(key))
 Base.setindex!(obj::Object{Symbol}, value, key::String) = setindex!(obj, value, Symbol(key))
-Base.delete!(obj::Object{String}, key::Symbol) = delete!(obj, String(key))
+Base.delete!(obj::Object{String,V}, key::AbstractString) where {V} = _delete!(obj, String(key))
+Base.delete!(obj::Object{String,V}, key::Symbol) where {V} = _delete!(obj, String(key))
 Base.delete!(obj::Object{Symbol}, key::String) = delete!(obj, Symbol(key))
 Base.get(obj::Object, key, default) = get(() -> default, obj, key)
 Base.get(obj::Object{String}, key::Symbol, default) = get(obj, String(key), default)
@@ -166,7 +168,7 @@ Base.haskey(obj::Object{String}, key::Symbol) = haskey(obj, String(key))
 Base.haskey(obj::Object{Symbol}, key::String) = haskey(obj, Symbol(key))
 
 # setindex! finds node with key and sets value or inserts a new node
-function Base.setindex!(obj::Object{K,V}, value, key::K) where {K,V}
+function _setindex!(obj::Object{K,V}, value, key::K) where {K,V}
     root = obj
     while true
         if _k(obj) !== notset && isequal(_k(obj)::K, key)
@@ -180,9 +182,10 @@ function Base.setindex!(obj::Object{K,V}, value, key::K) where {K,V}
     Object{K,V}(obj, key, value)
     return value
 end
+Base.setindex!(obj::Object{K,V}, value, key::K) where {K,V} = _setindex!(obj, value, key)
 
 # delete! removes node
-function Base.delete!(obj::Object{K,V}, key::K) where {K,V}
+function _delete!(obj::Object{K,V}, key::K) where {K,V}
     # check empty case
     _ch(obj) === notset && return obj
     root = parent = obj
@@ -204,6 +207,7 @@ function Base.delete!(obj::Object{K,V}, key::K) where {K,V}
     end
     return root
 end
+Base.delete!(obj::Object{K,V}, key::K) where {K,V} = _delete!(obj, key)
 
 function Base.empty!(obj::Object)
     setfield!(obj, :child, notset)
@@ -214,4 +218,4 @@ end
 Base.setproperty!(obj::Object, sym::Symbol, val) = setindex!(obj, val, sym)
 Base.setproperty!(obj::Object{String}, sym::Symbol, val) = setindex!(obj, val, String(sym))
 
-Base.merge(a::NamedTuple, b::Object{String,Any}) = merge(a, (Symbol(k) => v for (k, v) in b))
\ No newline at end of file
+Base.merge(a::NamedTuple, b::Object{String,Any}) = merge(a, (Symbol(k) => v for (k, v) in b))
diff --git a/test/object.jl b/test/object.jl
index a9d826f..d691db0 100644
--- a/test/object.jl
+++ b/test/object.jl
@@ -293,6 +293,25 @@ using JSON, Test
         @test !haskey(empty_obj, "anything")
     end
 
+    @testset "AbstractString key support for parsed String objects" begin
+        obj = JSON.parse("{\"foo\": \"bar\"}")
+        s = "abc.foo.xyz"
+        k = split(s, ".")[2]
+
+        @test k isa SubString{String}
+        @test haskey(obj, k)
+        @test get(obj, k, nothing) == "bar"
+        @test obj[k] == "bar"
+
+        obj[k] = "baz"
+        @test obj["foo"] == "baz"
+
+        delete!(obj, k)
+        @test !haskey(obj, "foo")
+        @test get(obj, k, "default") == "default"
+        @test_throws KeyError obj[k]
+    end
+
     # Test enhanced haskey for Symbol objects with String keys
     @testset "Enhanced haskey for Symbol Objects" begin
         obj = JSON.Object{Symbol, Any}()
@@ -404,4 +423,4 @@ using JSON, Test
         @test merged_mixed.float == 3.14
         @test merged_mixed.bool == true
     end
-end
\ No newline at end of file
+end